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- Mobini, Shifteh, et al.
(författare)
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Urban flood damage claim analyses for improved flood damage assessment
- 2022
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Ingår i: International Journal of Disaster Risk Reduction. - : Elsevier BV. - 2212-4209. ; 77
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Tidskriftsartikel (refereegranskat)abstract
- Urban flood damage leads to major costs for private house owners, insurance companies, and water and wastewater utilities. Analysis of flood damage claims can be used to improve the understanding of the details of flood damage characteristics and reasons for drainage system failures. However, few studies have used data of this kind to investigate urban flood characteristics. We examined 3113 damage claim cases over 30 years (1992–2019) for the city of Malmö, Sweden. We quantified the distribution and frequency of both major and minor flood damages over this period. Our analysis showed that most floods occur in August, but we could not find any significant trend in the count of damage claims between 1992 till 2019. The main drivers of flood damages were rainfall and failure mechanisms in the drainage system. In total, 24.5% of properties suffered from repeated flood damages, 44% originating from combined sewer system connection and 17% from the separated sewer system. This highlights the importance of sewer system types in flood damage claims. In addition, there was an uneven claim count between insurance companies and owners per event. About 42% of insurance company claims were not accompanied by the owner's deductible claims. Our results highlight the need to further investigate the reason behind this difference and ways for better future planning to minimize the damage from flood events.
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| 5. |
- Eltarabily, Mohamed Galal, et al.
(författare)
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Comparative analysis of root growth modules in HYDRUS for SWC of rice under deficit drip irrigation
- 2021
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 13:14
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Tidskriftsartikel (refereegranskat)abstract
- Root distribution during rice cultivation is a governing factor that considerably affects soil water content (SWC) and root water uptake (RWU). In this study, the effects of activating root growth (using growth function) and assigning a constant average root depth (no growth during simulation) on SWC and RWU for rice cultivation under four deficit drip irrigation treatments (T90, T80, T70, and T60) were compared in the HYDRUS-2D/3D model version 3.03. A secondary objective was to investigate the effect of applied deficit irrigation treatments on grain yield, irrigation water use efficiency (IWUE), and growth traits of rice. The simulated DI system was designed to reflect a representative field experiment implemented in El-Fayoum Governorate, Egypt, during two successive seasons during 2017 and 2018. The deficit treatments (T90, T80, T70, and T60) used in the current study represent scenarios at which the first irrigation event was applied when the pre-irrigation average SWC within the upper 60 cm of soil depth was equal to 90%, 80%, 70%, and 60% of plant-available water, respectively. Simulation results showed that as water deficiency increased, SWC in the simulation domain decreased, and thereby, RWU decreased. The average SWC within the root zone during rice-growing season under different deficit treatments was slightly higher when activating root growth function than when considering constant average root depth. Cumulative RWU fluxes for the case of no growth were slightly higher than for the case of root growth function for T90, T80, and T70 accounting for 1289.50, 1179.30, and 1073.10 cm2, respectively. Average SWC during the growth season (24 h after the first irrigation event, mid-season, and 24 h after the last irrigation event) between the two cases of root growth was strongly correlated for T90, T80, T70, and T60, where r2 equaled 0.918, 0.902, 0.892, and 0.876, respectively. ANOVA test showed that there was no significant difference for SWC between treatments for the case of assigning root growth function while the difference in SWC among treatments was significant for the case of the constant average root depth, where p-values equaled 0.0893 and 0.0433, respectively. Experimental results showed that as water deficiency decreased, IWUE increased. IWUE equaled 1.65, 1.58, 1.31, and 1.21 kg m-3 for T90, T80, T70, and T60, respectively. Moreover, higher grain yield and growth traits of rice (plant height, tillers number plant-1, panicles length, panicle weight, and grain number panicles-1) were obtained corresponding to T90 as compared with other treatments. Activating the root growth module in HYDRUS simulations can lead to more precise simulation results for specific dates within different growth stages. Therefore, the root growth module is a powerful tool for accurately investigating the change in SWC during simulation. Users of older versions of HYDRUS-2D/3D (version 2.05 and earlier) should consider the limitations of these versions for irrigation scheduling.
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| 6. |
- Sörensen, Johanna, et al.
(författare)
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Re-thinking urban flood management – time for a regime shift
- 2016
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- Urban flooding is of growing concern due to increasing densification of urban areas, changes in land use, and climate change. The traditional engineering approach to flooding is designing single-purpose drainage systems, dams, and levees. These methods, however, are known to increase the long-term flood risk and harm the riverine ecosystems in urban as well as rural areas. In the present paper, we depart from resilience theory and suggest a concept to improve urban flood resilience. We identify areas where contemporary challenges call for improved collaborative urban flood management. The concept emphasizes resiliency and achieved synergy between increased capacity to handle stormwater runoff and improved experiential and functional quality of the urban environments. We identify research needs as well as experiments for improved sustainable and resilient stormwater management namely, flexibility of stormwater systems, energy use reduction, efficient land use, priority of transport and socioeconomic nexus, climate change impact, securing critical infrastructure, and resolving questions regarding responsibilities.
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| 7. |
- Taromideh, Fereshteh, et al.
(författare)
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Urban Flood-Risk Assessment : Integration of Decision-Making and Machine Learning
- 2022
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Ingår i: Sustainability (Switzerland). - : MDPI AG. - 2071-1050. ; 14:8
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Tidskriftsartikel (refereegranskat)abstract
- Urban flood-risk mapping is an important tool for the mitigation of flooding in view of continuing urbanization and climate change. However, many developing countries lack sufficiently detailed data to produce reliable risk maps with existing methods. Thus, improved methods are needed that can help managers and decision makers to combine existing data with more soft semi-subjective data, such as citizen observations of flood-prone and vulnerable areas in view of existing settlements. Thus, we present an innovative approach using the semi-subjective Analytic Hierarchy Process (AHP), which integrates both subjective and objective assessments, to help organize the problem framework. This approach involves measuring the consistency of decision makers’ judgments, generating pairwise comparisons for choosing a solution, and considering criteria and subcriteria to evaluate possible options. An urban flood-risk map was created according to the vulnerabilities and hazards of different urban areas using classification and regression-tree models, and the map can serve both as a first stage in advancing flood-risk mitigation approaches and in allocating warning and forecasting systems. The findings show that machine-learning methods are efficient in urban flood zoning. Using the city Rasht in Iran, it is shown that distance to rivers, urban drainage density, and distance to vulnerable areas are the most significant parameters that influence flood hazards. Similarly, for urban flood vulnerability, population density, land use, dwelling quality, household income, distance to cultural heritage, and distance to medical centers and hospitals are the most important factors. The integrated technique for both objective and semi-subjective data as outlined in the present study shows credible results that can be obtained without complicated modeling and costly field surveys. The proposed method is especially helpful in areas with little data to describe and display flood hazards to managers and decision makers.
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| 8. |
- Verma, Sangeeta, et al.
(författare)
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Simplified SMA-inspired 1-parameter SCS-CN model for runoff estimation
- 2018
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Ingår i: Arabian Journal of Geosciences. - : Springer Science and Business Media LLC. - 1866-7511 .- 1866-7538. ; 11:15
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Tidskriftsartikel (refereegranskat)abstract
- This study proposes a simplified 1-parameter SCS-CN model (M5) based on Mishra-Singh (2002) model and soil moisture accounting (SMA) procedure for surface runoff estimation and compares its performance with the existing SCS-CN method (SCS, 1956) (M1), Michel 1-P model (Water Resour Res 41:1-6, 2005) (M2), Sahu 1-P model (Hydrol Process 21:2872-2881, 2007) (M3), and Ajmal et al. model (J Hydrol 530:623-633, 2015) (M4) using large rainfall–runoff dataset of 48,763 events from123 USDA-ARS watersheds. The performance of models was evaluated using three statistical error indices such as Nash-Sutcliffe efficiency (NSE), root mean square error (RMSE), percentage bias (PBIAS), and rank and grading system (RGS). Based on the results obtained, the models can be ranked as follows: M5 > M4 > M3 > M1 > M2, i.e., model M5 outperformed all the remaining four models M1–M4 and hence is recommended for field applications.
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| 9. |
- Abdiyev, Kaldibek, et al.
(författare)
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Review of Slow Sand Filtration for Raw Water Treatment with Potential Application in Less-Developed Countries
- 2023
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Ingår i: Water (Switzerland). - 2073-4441. ; 15:11
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Forskningsöversikt (refereegranskat)abstract
- Providing safe drinking water to people in developing countries is an urgent worldwide water problem and a main issue in the UN Sustainable Development Goals. One of the most efficient and cheapest methods to attain these goals is to promote the use of slow sand filters. This review shows that slow sand filters can efficiently provide safe drinking water to people living in rural communities not served by a central water supply. Probably, the most important aspect of SSF for developing and less-developed countries is its function as a biological filter. WASH problems mainly relate to the spread of viruses, bacteria, and parasites. The surface and shallow groundwater in developing countries around urban areas and settlements are often polluted by domestic wastewater containing these microbes and nutrients. Thus, SSF’s function is to treat raw water in the form of diluted wastewater where high temperature and access to nutrients probably mean a high growth rate of microbes and algae but probably also high predation and high efficiency of the SSF. However, factors that may adversely affect the removal of microbiological constituents are mainly low temperature, high and intermittent flow rates, reduced sand depth, filter immaturity, and various filter amendments. Further research is thus needed in these areas, specifically for developing countries.
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| 10. |
- Aboulila, Tarek Selim, et al.
(författare)
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Assessment of inter-plant emitter distance and effects of irrigation water salinity on APRDI using Hydrus-2D
- 2011
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Ingår i: European Journal of Scientific Research. - 1450-216X. ; 58, s. 266-277
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedModern irrigation techniques are becoming increasingly important in water-scarce countries. In this study, a two-dimensional water and solute transport model, Hydrus-2D, was used to assess the impact of inter-plant emitter distance (IPED) and irrigation water salinity on soil moisture and salinity distribution as well as on water balance components under alternate partial root-zone surface drip irrigation (APRDI) of tomato growing in loamy sand soil. Three IPED (20, 30, and 40 cm) and three irrigation water salinity levels (0, 1, and 2 dS/m) were used to execute different simulation scenarios. Simulation results indicated that the fluctuations in water content within the root zone were more pronounced in case of 20 cm IPED. The root water uptake increased as the IPED decreased. Using brackish irrigation water in APRDI caused significant augmentation in soil salinity in the top soil layer especially at the location of plant. The impact of irrigation water salinity on root water uptake increased as the IPED increased. As irrigation water salinity increased the root water uptake decreased. At plant location, soil salinity reached its highest values at the top soil layer in case of 30 and 40 cm IPED with brackish irrigation water. However, high soil salinity values were observed between the 40 and 65 cm depths in case of 20 cm IPED. Based on the results, it appears that APRDI with non-saline irrigation water is more effective with short IPED considering that approximately half of the root system was exposed to drying cycle. In addition, short IPED is recommended in APRDI when using brackish irrigation water especially for plants with shallow root system taking into account crop salinity tolerance.
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