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  • 1.
    Andersson, Lotta
    et al.
    SMHI, Core Services.
    Rosberg, Jörgen
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Estimating catchment nutrient flow with the HBV-NP model: Sensitivity to input data2005In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, no 7, p. 521-532Article in journal (Refereed)
    Abstract [en]

    The dynamic catchment model HBV-N has been further developed by adding routines for phosphorus transport and is now called the HBV-NP model. The model was shown to satisfactorily simulate nutrient dynamics in the Ronnea catchment (1 900 km(2)). Its sensitivity to input data was tested, and results demonstrated the increased sensitivity to the selection of input data on a subcatchment scale when compared with the catchment scale. Selection of soil and land use databases was found to be critical in some subcatchments but did not have a significant impact on a catchment scale. Although acceptable on a catchment scale, using templates and generalization, with regards to emissions from point sources and rural households, significantly decreased model performance in certain subcatchments when compared with using more detailed local information. A division into 64 subcatchments resulted in similar model performance at the catchment outlet when compared with a lumped approach. Adjusting the imported matrixes of the regional leaching of nitrogen, from agricultural land, against mean subcatchment water percolation did not have a significant impact on the model performance.

  • 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.
    Arheimer, Berit
    et al.
    SMHI, Research Department, Hydrology.
    Andreasson, Johan
    SMHI, Professional Services.
    Fogelberg, S
    Johnsson, H
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Persson, K
    Climate change impact on water quality: Model results from southern Sweden2005In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, no 7, p. 559-566Article in journal (Refereed)
    Abstract [en]

    Starting from six regional climate change scenarios, nitrogen leaching from arable-soil, water discharge, and nitrogen retention was modeled in the Ronnea catchment. Additionally, biological response was modeled in the eutrophic Lake Ringsjon. The results are compared with similar studies on other catchments. All scenarios gave similar impact on water quality but varied in quantities. However, one scenario resulted in a different transport pattern due to less-pronounced seasonal variations in the hydrology. On average, the study shows that, in a future climate, we might expect: i) increased concentrations of nitrogen in the arable root zone (+50%) and in the river (+13%); ii) increased annual load of nitrogen from land to sea (+22%) due to more pronounced winter high flow; moreover, remote areas in the catchment may start to contribute to the outlet load; iii) radical changes in lake biochemistry with increased concentrations of total phosphorus (+50%), total nitrogen (+20%), and planktonic algae such as cyanobacteria (+80%).

  • 4.
    Arheimer, Berit
    et al.
    SMHI, Research Department, Hydrology.
    Lowgren, M
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Rosberg, Jörgen
    SMHI, Research Department, Hydrology.
    Integrated catchment modeling for nutrient reduction: Scenarios showing impacts, potential, and cost of measures2005In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, no 7, p. 513-520Article in journal (Refereed)
    Abstract [en]

    A hydrological-based model (HBV-NP) was applied to a catchment (1900 km(2)) in the southern part of Sweden. Careful characterization of the present load situation and the potential for improved treatment or reduced soil leaching were analyzed. Several scenarios were modeled to find strategies to reach the Swedish environmental goals of reducing anthropogenic nitrogen load by 30% and phosphorus load by 20%. It was stated that the goals could be reached by different approaches that would affect different polluters and social sectors. However, no single measure was enough by itself. Instead, a combination of measures was necessary to achieve the goals. The nitrogen goal was the most difficult to attain. In order to be cost-effective, these measures should be applied to areas contributing the most to the net loading of the sea. This strategy could reduce the costs by 70%-80% when compared with implementing the measures in the entire catchment. Integrated catchment models may thus be helpful tools for reducing costs in environmental control programs.

  • 5.
    Arheimer, Berit
    et al.
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Kväveretention i svenska sjöar och vattendrag – betydelse för utsläpp från reningsverk2007Report (Other academic)
    Abstract [en]

    This report has been compiled on request of the Swedish Environmental Protection Agency to facilitate the discussion with the EU Commission. The EU Commission has announced that it will take Sweden to the European Court of Justice for failing to ensure proper treatment of urban waste water according to the Urban Waste Water Treatment Directive (Directive 91/271/EEC). In Sweden natural nitrogen removal (retention) in waterbodies is considered as part of the treatment of emissions, when transported to the sea. Nitrogen retention is a well-known phenomenon that includes several natural biogeochemical processes, which permanently remove nitrogen from the water. The effect may be considerable in areas with many lakes. Sweden has 92 000 lakes larger than 1 hectare. It is rather normal with 30-70% nitrogen retention in Swedish lakes and rivers. The main process for natural nitrogen retention is denitrification, which is the same process that is applied for biological treatment in waste water plants. Natural retention is hard to measure, however, and has to be estimated based on several assumptions like so many other fluxes in nature. In Sweden a model system has been developed for large-scale calculation of nutrient transport, including retention, from land to the sea, with relatively high geographic resolution. The system couples field-scale models with catchment models and is scientifically documented and reviewed. It has been applied since 1997 for international reporting to HELCOM. The catchment model (HBVNP) is tuned and evaluated against monitored time-series of measurements where such are available. The nitrogen retention that is calculated with HBV-NP is composed of nitrogen that is permanently transferred to the atmosphere and sediment, and which therefore will not further contribute to the eutrophication of water systems.

  • 6.
    Arheimer, Berit
    et al.
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Lessons learned? Effects of nutrient reductions from constructing wetlands in 1996–2006 across Sweden2016In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, p. 1-11Article in journal (Refereed)
  • 7. Dahl, M
    et al.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Comparison of four models simulating phosphorus dynamics in Lake Vanern, Sweden2004In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 8, no 6, p. 1153-1163Article in journal (Refereed)
    Abstract [en]

    This paper compares four water quality models applied to Lake Vanern, Sweden. The comparison is focused on phosphorus, the primary limiting nutrient in Lake Vanern. Two of the models, FYRISA and HBV-NP, are simple and were developed as parts of catchment models. Two other models, called LEEDS and MOM are more comprehensive lake models. The models were calibrated using data from the period 1985-1992 and validated using data from the period 1993-2000. The fit to calibration data is similar for the FYRISA, HBV-NP, and LEEDS models, and slightly worse for the BIOLA model. All models fit the validation data almost as well as the calibration data. The models behaviour was tested in two representative scenarios. An increase of emissions by 40% from a pulp and paper mill has a negligible effect on the water quality, while a decrease in phosphorus load by 14% (accomplished by better waste-water treatment in rural households) gives a considerable decrease in phosphorus concentration in the lake. Still, the results of the scenarios vary between the models.

  • 8.
    Lindström, Göran
    et al.
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Rosberg, Jörgen
    SMHI, Research Department, Hydrology.
    Strömqvist, Johan
    SMHI, Research Department, Hydrology.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Development and testing of the HYPE (Hydrological Predictions for the Environment) water quality model for different spatial scales2010In: HYDROLOGY RESEARCH, ISSN 1998-9563, Vol. 41, no 3-4, p. 295-319Article in journal (Refereed)
    Abstract [en]

    The HYPE model is a hydrological model for small-scale and large-scale assessments of water resources and water quality, developed at the Swedish Meteorological and Hydrological Institute during 2005-2007. In the model, the landscape is divided into classes according to soil type, land use and altitude. In agricultural lands the soil is divided into three layers, each with individual computations of soil wetness and nutrient processes. The model simulates water flow and transport and turnover of nitrogen and phosphorus. Nutrients follow the same pathways as water in the model: surface runoff, macropore flow, tile drainage and outflow from individual soil layers. Rivers and lakes are described separately with routines for turnover of nutrients in each environment. Model parameters are global, or coupled to soil type or land use. The model was evaluated both by local calibrations to internal variables from different test basins and to data on discharge and nutrients from a large number of small basins. In addition, the estimated parameters were transferred to two larger basins in southern Sweden: River Ronnea and River Vindan. The resulting simulations were generally in good agreement with observations.

  • 9.
    Olsson, Jonas
    et al.
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Bengtsson, Lisa
    SMHI, Research Department, Meteorology.
    Pechlivanidis, Ilias
    SMHI, Research Department, Hydrology.
    Berg, Peter
    Körnich, Heiner
    SMHI, Research Department, Meteorology.
    Distance-dependent depth-duration analysis in high-resolution hydro-meteorological ensemble forecasting: A case study in Malmo City, Sweden2017In: Environmental Modelling & Software, ISSN 1364-8152, E-ISSN 1873-6726, Vol. 93, p. 381-397Article in journal (Refereed)
  • 10.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    BIOLA - Biogeochemical Lake Model Manual2003Report (Other academic)
  • 11.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    HBV-NP Model Manual2007Report (Other academic)
  • 12.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Model description of BIOLA - a biogeochemical lake model2002Report (Other academic)
    Abstract [en]

    The biogeochemical lake model BIOLA was developed to be used for eutrophication studies in

    Sweden

    . Eutrophication is a threat for lakes in populated areas, and this model was developed to be

    a tool for managing lakes suffering from eutrophication. There are several measures that can be

    taken to reduce eutrophication. When considering different measures simulations of their effects,

    with models such as BIOLA, can contribute with information.

    The model is a biogeochemical lake module coupled to a one-dimensional hydrodynamic model.

    The model simulates the continuous change of lake stratification and water quality due to weather,

    inflow

    , outflow and biogeochemical processes in the lake and in the sediments. It simulates changes

    over time in nutrient and biological state at different depths. The most important variables simulated

    by the model are inorganic nutrients and phytoplankton in the water. Other variables include

    nutrients and organic matter in the sediments.

    The model has shown to be able to simulate changing nutrient and plankton dynamics. The result

    from three studied lakes are reviewed.

  • 13.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Modeling the response of eutrophication control measures in a Swedish lake2005In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, no 7, p. 552-558Article in journal (Refereed)
    Abstract [en]

    The response of a biogeochemical lake model (BIOLA) to different eutrophication management actions has been studied in a eutrophic lake. Management actions included in the study were nutrient load reduction, sediment manipulation, biomanipulation, and herbicide application. The model was used to simulate nutrient and biomass concentrations in the lake during the 1990s. During the same period, management scenarios were also simulated. Several ecological parameters were calibrated to better simulate the behavior of the chosen lake, but there were still some difficulties with phosphate. This indicated that further model development is necessary. The most favorable development within the lake was found for scenarios with nutrient load reduction and biomanipulation through planktivorous fish reduction. Reducing both the nitrogen and phosphorus loads had a greater effect on the lake's water quality than simply reducing just one of the nutrients.

  • 14.
    Pers, Charlotta
    et al.
    SMHI, Research Department, Hydrology.
    Persson, I
    Simulation of a biogeochemical model in different lakes2003In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 34, no 5, p. 543-558Article in journal (Refereed)
    Abstract [en]

    Eutrophication, caused by nutrients leached from soil and emitted from point sources, is a well-known problem in many Swedish lakes. There are several countermeasures that can be used to reduce eutrophication. A model that can simulate the biogeochemical response to different management scenarios may help with nutrient reducing strategies. Results from applications with such a model to different types of lakes are presented in this paper. The most important variables simulated by the model are dissolved nutrient concentrations (nitrogen and phosphorus) and phytoplankton. Other variables include nitrogen fixating cyanobacteria, sediments, and zooplankton. In total, 14 state variables are simulated. Nutrients are supplied through tributaries, and the temperature and vertical mixing forced by meteorological input. The model is able to simulate effects of changing nutrients and plankton dynamics. It is promising as an instrument for evaluating various measures to improve water quality in lakes. However, for the lakes the model has been applied to, the model has been calibrated to available observations. Non-monitored lakes could also be interesting to simulate, therefore the parameters of the model set-ups are discussed in this paper.

  • 15.
    Pers, Charlotta
    et al.
    SMHI, Research Department, Hydrology.
    Rahm, Lars
    SMHI, Research Department, Oceanography.
    Jonsson, A
    Bergstrom, A K
    Jansson, M
    Modelling dissolved organic carbon turnover in humic Lake Ortrasket, Sweden2001In: Environmental Modelling and Assessment, ISSN 1420-2026, E-ISSN 1573-2967, Vol. 6, no 3, p. 159-172Article in journal (Refereed)
    Abstract [en]

    The organic carbon balance of a lake with high input of allochthonous organic carbon is modelled integrating physical, chemical and biological processes. The physical model captures the behaviour of real thermal stratification in the lake for different flow situations during the period 1993-1997. The dissolved organic carbon model is based on simulated trajectories of water parcels. By tracking parcels, account is kept of environmental factors such as temperature and radiation as well as DOC quality for each parcel, The DOC concentration shows seasonal variations primarily dependent on inflow. The organic matter degradation (bacterial- and photodegradation) in the lake amounts to 1.5-2.5 mg C l(-1) yr(-1), where photooxidation is responsible for approximately 10%. The estimated DIC production in the lake is large compared to sediment mineralisation and primary production. The main conclusion is that the model with the selected parameterisations of the degradation processes reasonably well describes the DOC dynamics in a forest lake.

  • 16.
    Pers, Charlotta
    et al.
    SMHI, Research Department, Hydrology.
    Temnerud, Johan
    SMHI, Research Department, Hydrology.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Modelling water, nutrients, and organic carbon in forested catchments: a HYPE application2016In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 30, no 18, p. 3252-3273Article in journal (Refereed)
  • 17.
    Strombäck, Lena
    et al.
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Strömqvist, Johan
    SMHI, Research Department, Hydrology.
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Gustavsson, Jens
    SMHI.
    A web based analysis and scenario tool for eutrophication of inland waters for Sweden and Europe2019In: Environmental Modelling & Software, ISSN 1364-8152, E-ISSN 1873-6726, Vol. 111, p. 259-267Article in journal (Refereed)
  • 18. Tonderski, K S
    et al.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Modeling the impact of potential wetlands on phosphorus retention in a Swedish catchment2005In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, no 7, p. 544-551Article in journal (Refereed)
    Abstract [en]

    In southern Sweden, wetlands are constructed to remove nitrogen (N) in agricultural catchments. The possible effects of such wetlands on riverine phosphorus (P) were also estimated using input-output data from three well-monitored wetlands. This was done to formulate a simple model for removal of P that is dependent on inflow characteristics. Next, the N- and P-reducing effects of wetlands were modeled on a catchment scale (1900 km 2) using the HBV-NP model and various assumptions about the wetland area and location. All three wetlands functioned as sinks for total P (tot-P) and for total suspended solids (TSS) with a removal of 10% to 31% and 28% to 50%, respectively. Mean P-removal rates of 17-49 kg ha(-1) yr(-1) were well simulated with the model. Catchment scale simulations indicated that wetlands were more efficient (in percentage of load) as traps for P than for N and that this may motivate the construction of wetlands for P removal far upstream from the catchment outlet.

  • 19. Winterdahl, Mattias
    et al.
    Laudon, Hjalmar
    Lyon, Steve W.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Bishop, Kevin
    Sensitivity of stream dissolved organic carbon to temperature and discharge: Implications of future climates2016In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 121, no 1, p. 126-144Article in journal (Refereed)
    Abstract [en]

    Dissolved organic carbon (DOC) is a significant constituent in aquatic ecosystems with concentrations in streams influenced by both temperature and water flow pathway dynamics associated with changes in discharge (streamflow). We investigated the sensitivity of DOC concentrations in 12 high-latitude headwater streams to changes in temperature and discharge using a mathematical model. The implications of differences in sensitivities were explored by using downscaled projections of air temperature and discharge to simulate possible trajectories of DOC concentrations in a changing climate. We found two distinct responses: (i) catchments where stream DOC sensitivity was high to temperature but low to discharge and (ii) catchments where stream DOC sensitivity was low to temperature but high to discharge. Streams with strong seasonal DOC dynamics were more sensitive to temperature changes than nonseasonal systems. In addition, stream DOC sensitivity to discharge was strongly correlated with vertical soil water DOC differences in the near-stream zone. Simulations of possible future changes in DOC concentrations indicated median increases of about 4-24% compared to current levels when using projections of air temperature and discharge but even larger increases were observed for base flow concentrations (13-42%). Streams with high-temperature sensitivity showed the largest increases in DOC concentrations. Our results suggest that future climatic changes could bring significant increases in surface water DOC concentrations in boreal and hemiboreal areas but that the response ultimately is dependent on vertical soil solution DOC differences and soil organic carbon distribution.

  • 20. Yin, Yunxing
    et al.
    Jiang, Sanyuan
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Yang, Xiaoying
    Liu, Qun
    Yuan, Jin
    Yao, Mingxing
    He, Yi
    Luo, Xingzhang
    Zheng, Zheng
    Assessment of the Spatial and Temporal Variations of Water Quality for Agricultural Lands with Crop Rotation in China by Using a HYPE Model2016In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 13, no 3Article in journal (Refereed)
    Abstract [en]

    Many water quality models have been successfully used worldwide to predict nutrient losses from anthropogenically impacted catchments, but hydrological and nutrient simulations with limited data are difficult considering the transfer of model parameters and complication of model calibration and validation. This study aims: (i) to assess the performance capabilities of a new and relatively more advantageous model, namely, Hydrological Predictions for the Environment (HYPE), that simulates stream flow and nutrient load in agricultural areas by using a multi-site and multi-objective parameter calibration method and (ii) to investigate the temporal and spatial variations of total nitrogen (TN) and total phosphorous (TP) concentrations and loads with crop rotation by using the model for the first time. A parameter estimation tool (PEST) was used to calibrate parameters. Results show that the parameters related to the effective soil porosity were highly sensitive to hydrological modeling. N balance was largely controlled by soil denitrification processes. P balance was influenced by the sedimentation rate and production/decay of P in rivers and lakes. The model reproduced the temporal and spatial variations of discharge and TN/TP relatively well in both calibration (2006-2008) and validation (2009-2010) periods. Among the obtained data, the lowest Nash-Suttclife efficiency of discharge, daily TN load, and daily TP load were 0.74, 0.51, and 0.54, respectively. The seasonal variations of daily TN concentrations in the entire simulation period were insufficient, indicated that crop rotation changed the timing and amount of N output. Monthly TN and TP simulation yields revealed that nutrient outputs were abundant in summer in terms of the corresponding discharge. The area-weighted TN and TP load annual yields in five years showed that nutrient loads were extremely high along Hong and Ru rivers, especially in agricultural lands.

1 - 20 of 20
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