| 1. |
- Haghighatafshar, Salar, et al.
(författare)
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A physically based model for mesoscale SuDS–an alternative to large-scale urban drainage simulations
- 2019
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797. ; 240:15 June 2019, s. 527-536
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Tidskriftsartikel (refereegranskat)abstract
- This study presents a deterministic, lumped model to simulate mesoscale sustainable drainage systems (SuDS) based on a conceptualization of the stormwater control measures (SCMs) making up the system and their influence on the runoff process. The conceptualization mainly relies on parameters that are easily quantifiable based on the physical characteristics of the SCMs. Introducing a nonlinear reservoir model at the downstream end of the SuDS results in a fast model that can realistically describe the runoff process at low computational cost. Modelled hydrographs for the study area in Malmö, Sweden, matched data with regard to the overall shape of the hydrograph as well as the peak discharge and lag time. These output parameters are critical factors to be considered in the design of large systems consisting of mesoscale SuDS. The algebraic foundation of the developed model makes it suitable for large-scale applications (e.g., macroscale), where the simulation time is a decisive factor. In this respect, city-wide optimization studies for the most efficient location and implementation of SuDS are substantially accelerated due to fast and easy model setup. Moreover, the simplicity of the model facilitates more effective communication between all the actors engaged in the urban planning process, including political decision makers, urban planners, and urban water engineers.
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| 2. |
- Bengtsson, Lars, et al.
(författare)
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Hydrology of transport systems
- 2017
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Ingår i: Handbook of Applied Hydrology, Second Edition. - 9780071835091
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Bokkapitel (refereegranskat)
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| 3. |
- Göransson, Gunnel, et al.
(författare)
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A methodology for estimating risks associated with landslides of contaminated soil into rivers
- 2014
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 472, s. 481-495
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Tidskriftsartikel (refereegranskat)abstract
- Urban areas adjacent to surface water are exposed to soil movements such as erosion and slope failures (landslides). A landslide is a potential mechanism for mobilisation and spreading of pollutants. This mechanism is in general not included in environmental risk assessments for contaminated sites, and the consequences associated with contamination in the soil are typically not considered in landslide risk assessments. This study suggests a methodology to estimate the environmental risks associated with landslides in contaminated sites adjacent to rivers. The methodology is probabilistic and allows for datasets with large uncertainties and the use of expert judgements, providing quantitative estimates of probabilities for defined failures. The approach is illustrated by a case study along the river Gota Alv, Sweden, where failures are defined and probabilities for those failures are estimated. Failures are defined from a pollution perspective and in terms of exceeding environmental quality standards (EQSs) and acceptable contaminant loads. Models are then suggested to estimate probabilities of these failures. A landslide analysis is carried out to assess landslide probabilities based on data from a recent landslide risk classification study along the river Gota Alv. The suggested methodology is meant to be a supplement to either landslide risk assessment (LRA) or environmental risk assessment (ERA), providing quantitative estimates of the risks associated with landslide in contaminated sites. The proposed methodology can also act as a basis for communication and discussion, thereby contributing to intersectoral management solutions. From the case study it was found that the defined failures are governed primarily by the probability of a landslide occurring. The overall probabilities for failure are low; however, if a landslide occurs the probabilities of exceeding EQS are high and the probability of having at least a 10% increase in the contamination load within one year is also high.
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| 4. |
- Zhu, Fangfang, et al.
(författare)
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A logarithmic bottom boundary layer model for the unsteady and non-uniform swash flow
- 2022
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Ingår i: Coastal Engineering. - : Elsevier BV. - 0378-3839. ; 172
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a bottom boundary layer model for the unsteady and non-uniform flow in the swash zone, by extending the momentum integral method so as to include spatial gradients. The developed model is further incorporated into a hydrodynamic model based on the Nonlinear Shallow Water Equations. Two swash zone cases are examined to investigate the effect of the inclusion of spatial gradients. In the first of the two, boundary layer development under non-breaking periodic waves formulated by Carrier and Greenspan (1958) is investigated (wave-driven swash). Results show that the spatial gradients have the most pronounced effect in the lower swash, and in the region just seaward. In both these regions the spatial gradients enhance (diminish) onshore (offshore) bed shear stress, thus potentially contributing to onshore sediment transport under non-breaking waves. The second case investigated is the Kikkert et al. (2012) dam-break swash event (bore-driven swash). The model results are qualitatively and quantitatively accurate when compared against the laboratory measurements, and the velocities in the later backwash agree more closely with the measurements than those of Briganti et al. (2011). Results show that the inclusion of spatial gradients also favours onshore sediment transport in the lower swash. In addition, the bottom boundary layer is more fully developed in the uprush tip, resulting in smaller bed shear stress in the upper swash. The extended momentum integral method thus appears to capture more comprehensively the swash boundary layer, and the approach, therefore, offers a way forward in more accurate reproduction of swash dynamics in computational modelling.
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| 5. |
- Adell, Anna, et al.
(författare)
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Morphological development of a small-scale beach nourishment in a non-tidal area
- 2023
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Ingår i: The Proceedings of the Coastal Sediments 2023. - : WORLD SCIENTIFIC.
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Konferensbidrag (refereegranskat)abstract
- Combining hard and soft costal protection solutions can be an appropriate measure to enhance structure lifetime. This study aims to quantify the morphological evolution of the nourished stretch and adjacent coastlines. A small-scale beach nourishment has been performed in front of a rock revetment at site in Faxe Ladeplads in Zealand, Denmark. The overall objective is to learn more about the dynamics of small-scale nourishments in low energy environments. Monitoring techniques include repeated topographic (Trimble RTK-GPS, drone surveying) and bathymetric (single beam) measurements. To measure the hydrodynamic conditions two surface acceleration buoys deployed at -4 and -7 m water depth were used. Sediment volumes from nourishments of size 70,000 m3 and 20,000 m3 redistributed relatively quickly. The nourished material built up the cross-shore profile and a longshore bar in this area, and distributed sediments in the direction of the dominant littoral drift (SW). Results suggest that the morphological evolution of the nourishment is dependent on local hydrodynamic conditions and local geomorphology. These findings have implications for the main objectives of preventing wave overtopping onto an adjacent coastal road during extreme events and restoring a beach for recreation.
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| 6. |
- Agustin, Sanchez-Arcilla, et al.
(författare)
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Introduction
- 2008
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Ingår i: Journal of Hydraulic Research. - 0022-1686. ; 46:2, s. 179-182
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Almström, Björn, et al.
(författare)
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Decision support tool to mitigate ship-induced erosion in non-uniform, sheltered coastal fairways
- 2022
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Ingår i: Ocean and Coastal Management. - : Elsevier BV. - 0964-5691. ; 225
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Tidskriftsartikel (refereegranskat)abstract
- The negative impact of maritime traffic in terms of shore erosion in sheltered coastal fairways can be mitigated by sustainable fairway management. Mitigation measures include regulating the ship traffic in terms of speed, routes, or size of ships, but can also involve erosion protection along a fairway. For effective shoreline management of a fairway, it is essential to predict ship waves, to identify sites with potential erosion problems, and to investigate the effectiveness of different measures before implementing them. Several attempts have been made to develop site-specific criteria for managing ship waves. However, few available generic models consider primary waves generated by large ships in confined fairways. Therefore, a tool for supporting decisions in fairway management was developed. The decision support tool is based on simplified formulas for ship- and wind-wave prediction, combined in a framework that enables automatic, rapid assessments on large spatial and temporal scales. Moreover, the tool requires only readily available input data, such as data on AIS, bathymetry, shoreline geometry, wind, fairway centreline, and grain size. The output from the model includes ship and wind wave heights and potential erosion sites. The decision support tool was applied to the Furusund Fairway, Sweden, by simulating one year of ship traffic to validate its capability of identifying potential erosion sites. The simulation demonstrated that the tool was capable of identifying known erosion sites in the fairway. Additionally, scenarios with different speed regulation strategies for the Furusund Fairway were investigated using the decision support tool. Overall, it is concluded that the developed tool enables rapid assessment of ship waves, wind waves, and potential erosion over large areas in fairways.
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| 8. |
- Almström, Björn, et al.
(författare)
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Experiences of nature-based solutions for mitigating ship-induced erosion in confined coastal waters
- 2022
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Ingår i: Ecological Engineering. - : Elsevier BV. - 0925-8574. ; 180
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Tidskriftsartikel (refereegranskat)abstract
- Hydrodynamic forces from ships operating in sheltered, confined fairways can result in increased wave impact and sediment transport leading to loss of land and habitats. Nature-based solutions (NBS) offer the potential to mitigate ship-induced erosion and increase biodiversity and ecosystem services. The aim of this study is to evaluate the performance of NBS in a sheltered, confined fairway located in a cold, temperate region. The case study presents the results of a 2.5-year study of the morphologic response at two sites where NBS was implemented to mitigate bluff erosion and at one site where NBS was implemented to mitigate the retreat of a reed belt. Moreover, a qualitative assessment was made of the vegetation development at the sites. The results showed that fine sediments with planted vegetation could not withstand the hydrodynamic forces induced by the ships. However, by adding sills as stabilizing structures, the forces were sufficiently attenuated for the vegetation to establish. The vegetation, which reduced the ship-generated waves and currents, was especially important during high water-level events when the energy dissipation by the sill decreased. Moreover, a small-scale nourishment was successfully applied to mitigate bluff erosion without negatively affecting sediment supply to an adjacent sandy beach. This study demonstrates that NBS can be implemented to retain erodible sediment and favour vegetation growth in fairways experiencing primary and secondary waves produced by large, ocean-going ships.
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| 9. |
- Almström, Björn, et al.
(författare)
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Predicting ship waves in sheltered waterways – An application of XBeach to the Stockholm Archipelago, Sweden
- 2021
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Ingår i: Coastal Engineering. - : Elsevier BV. - 0378-3839. ; 170
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Tidskriftsartikel (refereegranskat)abstract
- Predicting hydrodynamic forces from ship waves along a waterway is essential for managing a sustainable shoreline in fairways. In this context, a numerical model can be a useful tool for calculating ship waves in fairways with complex geometry. XBeach is a numerical model offering the potential to be a one-tool solution for simulating ship waves from the ship to the shore. However, XBeach has not been evaluated against field measurements of ship waves. Thus, the objective of this paper is (1) to compare XBeach against high-quality field measurements of ship waves and (2) to assess its general applicability to ship wave simulations through an extensive sensitivity analysis with regard to the main input parameters. Water level measurements from 42 passages of the M/S Baltic Princess in the Furusund navigational fairway in the Stockholm Archipelago were chosen to test and evaluate XBeach. The results showed that XBeach was able to generate and propagate the primary and secondary waves. Primary waves were reproduced well with a mean absolute error (MAE) of 3 cm for the drawdown height. The overall secondary wave field pattern was represented by XBeach; however, for the largest, single divergent wave comparison for height, period, and timing showed deviation from the observations. Overall, XBeach was found to be a robust model for ship wave applications, only requiring input data typically available. Sensitivity analysis for a generic hull, derived from the type of vessel studied and with the corresponding dimensions as the real hull, showed similar results enabling robust and reliable simulations without access to detailed technical drawings.
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| 10. |
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