| 1. |
- Haghighatafshar, Salar, et al.
(författare)
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An Innovative Method for Estimating Settling Velocity of Particles in Stormwater Using Absorbance Measurements and Modeling
- 2024
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Ingår i: Water Practice and Technology. - 1751-231X. ; 19:5, s. 1810-1821
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to develop a simple and rapid method for measuring the average settling velocity of particles in stormwater ponds. Water samples with suspended particles were collected from the bottom of a stormwater pond in Lund, Sweden. The absorbance in various samples was measured over 24 hours (at 600 nm wavelength) and then translated into total solids concentrations. A one-dimensional model based on the Mason-Weaver equation was coded in Python and solved. The absorbance measurements were used to calibrate the model, thereby quantifying settling velocities and dispersion coefficients for samples from different zones of the stormwater pond. The quantified settling velocities ranged from 40 to 200 mm/h for fast-settling particles and from 2 to 8 mm/h for slow-settling particles. The developed methodology provided a mass estimate of the two modeled particle groups (i.e., fast- and slow-settling particles). Based on the model estimates, fast-settling particles dominated all samples, constituting 70–90% of the total solid mass. Due to its simplicity and inexpensiveness, this methodology is a potential alternative to more demanding and complicated methodologies used for measuring particle velocities in sedimentation systems.
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| 2. |
- Haghighatafshar, Salar, et al.
(författare)
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Deep Learning for Modelling of Urban Drainage Networks: A Physics-informed Surrogate Model Using Measured and Simulated Data
- 2022
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Ingår i: Proceedings of IWA World Water Congress & Exhibition, Copenhagen 2022.
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Konferensbidrag (refereegranskat)abstract
- City-wide climate adaptation for pluvial flood mitigation requires fast and reliable simulation tools. Considering the limitations of hydrodynamic models at city-scale simulations, data driven models have high potential in the development of surrogate tools. This study explores the Google DeepMind WaveNet™ model architecture to map hydrological response of catchments onto hydraulic parameters of the pipe network in a physically informed approach to deep learning. The WaveNet-based surrogate model successfully predicted hydraulic head and pipe flow in the network at average Normalized Nash-Sutcliffe Model Efficiency Indices of above 0.8, while boosting simulation speed by a factor of 1000. The developed AI model can be used for different assessment and optimization studies on the drainage network, thanks to its physics-informed structure.
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| 3. |
- Haghighatafshar, Salar, et al.
(författare)
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Management of urban floods based on tolerable consequences in an uncertain future
- 2022
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Ingår i: Proceedings of the 39th IAHR World Congress (Granada, 2022). ; , s. 6955-6963
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Konferensbidrag (refereegranskat)abstract
- Precipitation is intrinsically associated with high uncertainty, which is exacerbated exponentially over time—especially concerning climate change. However, the current design practice in urban drainage infrastructure remains firmly bound to deterministic assumptions regarding the design load. This approach is too simplified—focusing only on the return period of the design event—and ignores the complexity of drainage systems, the potential changes in catchment hydrology and the at-risk valuable assets within. Therefore, the current design approach is inherently an unsustainable practice that cannot deal with extreme uncertainties associated with urban drainage and flood resilience in changing climate and society. This paper examines the current deterministic design practice and encourages a collective discussion on the need for a paradigm shift in the engineering of pluvial floods toward a risk-based design. We believe that adopting a risk-based design will partially address the uncertainty and complexity of climate and urban drainage, respectively, although a method for the new practice in a risk-based design paradigm must be developed.
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| 4. |
- Haghighatafshar, Salar, et al.
(författare)
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Paradigm shift in engineering of pluvial floods: From historical recurrence intervals to risk-based design for an uncertain future
- 2020
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Ingår i: Sustainable Cities and Society. - : Elsevier BV. - 2210-6707. ; 61
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Tidskriftsartikel (refereegranskat)abstract
- Precipitation is intrinsically associated with high uncertainty, which is exacerbated exponentially over time—especially concerning climate change. However, the current design practice in urban drainage infrastructure remains firmly bound to deterministic assumptions regarding the design load. This approach is too simplified—focusing only on the return period of the design event—and ignores the complexity of drainage systems and the potential changes in catchment hydrology and the at-risk valuable assets within. Therefore, the current design approach is inherently an unsustainable practice that cannot deal with extreme uncertainties associated with urban drainage and flood resilience in changing climate and society. This paper examines the current deterministic design practice and encourages a collective discussion on the need for a paradigm shift in the engineering of pluvial floods toward a risk-based design. We believe that adopting a risk-based design will partially address the uncertainty and complexity of climate and urban drainage, respectively, although a method for the new practice in a risk-based design paradigm must be developed.
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| 5. |
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| 6. |
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| 7. |
- Laster Grip, Isabelle, et al.
(författare)
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A methodology for the assessment of compound sea level and rainfall impact on urban drainage networks in a coastal city under climate change
- 2021
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Ingår i: City and Environment Interactions. - : Elsevier BV. - 2590-2520. ; 12:December 2021
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Tidskriftsartikel (refereegranskat)abstract
- This study seeks to investigate how stormwater drainage systems in coastal cities respond to climate change in terms of simultaneous sea level rise and rainfall. 7.5 years of recorded rainfall and sea level data in the city of Trelleborg in Sweden were used to generate projections of future climate events based on the emission scenario RCP8.5. Twelve scenarios were formulated to represent rain and sea level in today’s (reference)- and future climate. Future rainfall was computed using regional climate model data together with the Delta Change Method. Sea-related data was represented with two variables, namely an average sea level and storm surges. The average sea level was calculated to reflect seasonal variation using a second-order Fourier analysis whilst raw gauge data was used to capture the storm surges. The two sea variables were then scaled to represent future projections of sea level rise and storm surges in the study area. The performance of the drainage system was simulated with MIKE Urban 1D model and the results were expressed through two indicators, number of flooded nodes and flood frequency. The results of this study reveal a tipping point is likely to be found between years 2075 and 2100, after which storm surges become a major driver for overwhelmed drainage system. It was also found that pluvial floods may become more likely and frequent during winters as time progresses. This has a great implication when deciding on adaptation measures.
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| 8. |
- Mottaghi, Misagh, et al.
(författare)
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Caring for Blue-Green Solutions (BGS) in Everyday Life: An Investigation of Recreational Use, Neighborhood Preferences and Willingness to Pay in Augustenborg, Malmö
- 2023
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Ingår i: Land. - : MDPI AG. - 2073-445X. ; 12:2
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we explore the production of socio-cultural values around blue-green solutions (BGS) through the perspective of care. We explore how values and preferences are formed through the complexity of everyday life engagements in a BGS environment. The data come from a questionnaire answered by 328 households in the neighborhood of Augustenborg in Malmö, Sweden. The questionnaire collects detailed information about inhabitants’ possible recreational use (through Likert scale questions) and willingness to pay (WTP) (estimated through contingent valuation). The study evaluates if and how people care to use, care to live with, and care to pay for BGS. The result shows that people in Augustenborg relate in different and sometimes contradictory ways to BGS. A well-used BGS environment does not per se make the environment successful or result in people preferring a BGS environment in the future. Building awareness about BGS seems to increase the willingness to pay, whereas recreational use seems to decrease it. The study reveals a landscape of care that is constantly being formed and transformed. This suggests that both planning and research needs to focus more on the relation between BGS and social use over time.
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| 9. |
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| 10. |
- Roth, Sara, et al.
(författare)
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The compound impact of rainfall, river flow and sea level on a watercourse through a coastal city: Methodology in making
- 2024
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Ingår i: City and Environment Interactions. - 2590-2520. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- Due to climate change, future weather conditions will become more extreme. During recent years, several severe damages have been caused by heavy rainfalls in combination with riverine events. Even though the effects of compound events are known to be influential for flood hazard, the method for investigating these types of events is a novel area of expertise. In this study, a methodology was developed to investigate a watercourse, acting as a part of a stormwater drainage system in an urban coastal area, in a hydrodynamic model to find areas prone to flooding. The method was applied for Ståstorpsån in Trelleborg, Sweden. The model was a unified model for seasonal variability and compound events with scenarios developed based on series of data representing normal values of the boundary conditions rainfall, river flow and sea level. The result was analysed graphically and statistically as a flood hazard. The data used was based on data collected during the past 10 years for rain and sea level and 16 years of simulated river flow. The constructed rain events from gauge data all had a return time of less than 10 years. Therefore, the chosen events are considered to represent normal levels. For Trelleborg, the results from the hydrodynamic model indicate that compound events will increase the flood hazard with anincreasing time horizon. The visual analysis converges with earlier flood events, and hotspots are generally seen around bridges and culverts. For the studied area, there is a large seasonal variation in the flood hazard and with climate change, all seasons will cause more severe flood hazards. The effects experienced during a summer event, which is the most severe event today, are to be expected for all seasons in 2100. The effect seen during summer eventsis a combination of all three drivers. However, rain intensity is likely to be more influential for normal events. When a certain threshold value for sea level is reached, sea level becomes the most influential driver, overtaking the other drivers in importance.
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