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Bahrami M, Roghani B, Tscheikner-Gratl F, Rokstad MM. A deep dive into green infrastructure failures using fault tree analysis. WATER RESEARCH 2024; 257:121676. [PMID: 38692259 DOI: 10.1016/j.watres.2024.121676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/29/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
Green Infrastructure has transformed traditional urban stormwater management systems by fostering a wide range of service functions. Despite their popularity, green infrastructure's performance can deteriorate over their lifecycle, leading to operational failures. The operation of green infrastructure has predominantly relied on reactive maintenance strategies. To anticipate malfunctions and enhance the performance of green infrastructure in the long run, failure data needs to be recorded so that deterioration processes and component vulnerabilities can be recognized, modelled and included in predictive maintenance schemes. This study investigates possible failures in representative GIs and provides insights into the most important events that should be prioritized in the data collection process. A method for qualitative Fault Tree Analysis using minimal cut sets are introduced, aiming to identify potential failures with the minimum number of events. To identify events of interest fault trees were constructed for bioswales, rain gardens and green roofs, for three groups of service function failures, namely runoff quantity control, runoff quality control and additional service functions. The resulting fault trees consisted of 45 intermediate and 54 basic events. The minimal cut set analysis identified recurring basic events that could affect operation among all three green infrastructure instances. These events are 'trash accumulation', 'clogging due to sediment accumulation', and 'overly dense vegetation'. Among all the possible cut sets, events such as 'plants not thriving', 'invasive plants taking over', and 'deterioration caused by external influences' could potentially disrupt most of the service functions green infrastructure provides. Furthermore, the analysis of interactions between component failures shows vegetation and filter media layer failures have the highest influence over other components. The constructed fault trees and identified basic events could be potentially employed for additional research on data collection processes and calculating the failure rates of green infrastructure and as a result, contribute to a shift toward their proactive operation and maintenance.
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Affiliation(s)
- Mahdi Bahrami
- Norwegian University of Science and Technology (NTNU), Department of Civil and Environmental Engineering, Water and Wastewater Engineering (VA) Group, Trondheim, Norway.
| | - Bardia Roghani
- Norwegian University of Science and Technology (NTNU), Department of Civil and Environmental Engineering, Water and Wastewater Engineering (VA) Group, Trondheim, Norway
| | - Franz Tscheikner-Gratl
- Norwegian University of Science and Technology (NTNU), Department of Civil and Environmental Engineering, Water and Wastewater Engineering (VA) Group, Trondheim, Norway
| | - Marius Møller Rokstad
- Norwegian University of Science and Technology (NTNU), Department of Civil and Environmental Engineering, Water and Wastewater Engineering (VA) Group, Trondheim, Norway
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Busker T, de Moel H, Haer T, Schmeits M, van den Hurk B, Myers K, Cirkel DG, Aerts J. Blue-green roofs with forecast-based operation to reduce the impact of weather extremes. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 301:113750. [PMID: 34597953 DOI: 10.1016/j.jenvman.2021.113750] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 09/10/2021] [Accepted: 09/11/2021] [Indexed: 06/13/2023]
Abstract
Conventional green roofs have often been criticised for their limited water buffer capacity during extreme rainfall events and for their susceptibility to droughts when additional irrigation is unavailable. One solution to these challenges is to create an extra blue water retention layer underneath the green layer. Blue-green roofs allow more stormwater to be stored, and the reservoir can act as a water source for the green layer throughout capillary rises. An automated valve regulates the water level of the system. It can be opened to drain water when extreme precipitation is expected. Therefore, the water buffer capacity of the system during extreme rainfall events can be maximised by integrating precipitation forecasts as triggers for the operation of the valve. However, the added value of this forecast-based operation is yet unknown. Accordingly, in this study, we design and evaluate a hydrological blue-green roof model that utilises precipitation forecasts. We test its performance to capture (extreme) precipitation and to increase evapotranspiration and evaporative cooling under a variety of precipitation forecast-based decision rules. We show that blue-green roofs can capture between 70 % and 97 % of extreme precipitation (>20 mm/h) when set to anticipate ensemble precipitation forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF). This capture ratio is considerably higher than that of a conventional green roof without extra water retention (12 %) or that of a blue-green roof that does not use forecast information (i.e., valve always closed; 59 %). Moreover, blue-green roofs allow for high evapotranspiration rates relative to potential evapotranspiration on hot summer days (around 70 %), which is higher than from conventional green roofs (30 %). This serves to underscore the higher capacity of blue-green roofs to reduce heat stress. Using the city of Amsterdam as a case study, we show the high upscaling potential of the concept: on average, potentially suitable flat roofs cover 13.3 % of the total area of the catchments that are susceptible to pluvial flood risk. If the 90th percentile of the ECMWF forecast is used, an 84 % rainfall capture ratio can translate into capturing 11 % of rainfall in flood-prone urban catchments in Amsterdam.
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Affiliation(s)
- Tim Busker
- Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, the Netherlands.
| | - Hans de Moel
- Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, the Netherlands
| | - Toon Haer
- Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, the Netherlands
| | - Maurice Schmeits
- Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, the Netherlands; Royal Netherlands Meteorological Institute (KNMI), De Bilt, 3731 GA, the Netherlands
| | - Bart van den Hurk
- Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, the Netherlands; Deltares, Delft, 2600 MH, the Netherlands
| | - Kira Myers
- Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, the Netherlands
| | | | - Jeroen Aerts
- Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, the Netherlands; Deltares, Delft, 2600 MH, the Netherlands
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Research Progress of Urban Floods under Climate Change and Urbanization: A Scientometric Analysis. BUILDINGS 2021. [DOI: 10.3390/buildings11120628] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Urban floods research has been attracting extensive attention with the increasing threat of flood risk and environmental hazards due to global climate change and urbanization. However, there is rarely a comprehensive review of this field and it remains unclear how the research topics on urban floods have evolved. In this study, we analyzed the development of urban floods research and explored the hotspots and frontiers of this field by scientific knowledge mapping. In total, 3314 published articles from 2006 to 2021 were analyzed. The results suggest that the number of published articles in the field of urban floods generally has an upward trend year by year, and the research focus has shifted from exploring hydrological processes to adopting advanced management measures to solve urban flood problems. Moreover, urban stormwater management and low impact development in the context of climate change and urbanization have gradually become research hotspots. Future research directions based on the status and trends of the urban floods field were also discussed. This research can not only inspire other researchers and policymakers, but also demonstrates the effectiveness of scientific knowledge mapping analysis by the use of the software CiteSpace and VOSviewer.
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