1,720,970 research outputs found
Climate-Informed Planning and Design of Urban Water Systems
Full text linkGlobal warming is expected to cause alterations of the climate with potential impacts on urban water systems. As the knowledge base on climate change expands, and regional climate projections become increasingly available to local water managers, the need for climate-informed tools and decision-support systems rises.
This thesis seeks to address local stakeholders needs for novel tools and frameworks for facilitating climate adaptation and to investigate how climate projections can inform the analyses. The work of this thesis has been conducted as part of the H2020 project BINGO
- Bringing INnovation to onGOing water management - a better future under climate change (Grant Agreement number 641739), where the principal goal has been to provide end-users in the water sector with practical tools and knowledge on climate change.
The thesis specifically attends to three main applications of urban water systems: 1) drinking water availability planning, 2) storm water infrastructure design, and 3) urban drainage systems planning. To support the overall aims of the thesis, the following objectives were defined:
1. Investigate local climate projections and their potential to provide decision-support in local climate adaptation
2. Evaluate climate projections’ applicability for design in current stormwater management practice in Norway
3. Develop climate-informed adaptation frameworks for Norwegian urban water systems
To pursue these objectives, a collection of regional climate projections for the city of Bergen, Norway, was produced, processed and assessed through various tools and techniques. This resulted in a rich ensemble of climate projections for the city, covering a range of emissions scenarios, parent global climate models, and downscaling methods. These projections have further been used as input to hydrologic and hydraulic models embraced by the three defined water sector applications. Through this, the application of climate projections in planning and design of urban water systems was demonstrated and assessed, and frameworks providing decision-support were proposed.
The assessment of the resulting climate projection ensemble emphasizes the general consensus in research that ensemble approaches are necessary to gain a holistic and reliable indication of future local climates, as choices of emissions scenario, parent GCM, predictor, and downscaling techniques all introduce their own range of uncertainty. This implies that climate projections should not be further applied in a traditional predict-then-act manner, but rather treated as what they are: possible scenarios of future climate, sooner than predictions, and ensembles rather than singular best-guess estimates.
To emerge at climate-informed design practices in Norway, the results of this thesis strongly suggest that existing tools and methods should be adjusted to handle a range of input scenarios rather than single event or time series inputs. This would allow a shift from prediction-based design, to a risk-oriented design of urban water systems and system components.
Finally, three main decision-support frameworks are proposed for climate adaptation in the water sector. The three frameworks incorporate a new dimension of climate change information into traditional tools known to the water sector. In addition to addressing the third, and last objective of this thesis, they also contribute to the principle goal of the BINGO project: to provide end-users in the water sector with practical tools and knowledge on climate change. Although the results are site specific, linking frameworks to existing tools ensures scalability and transferability of methodologies
Digitalising optimisation of early phase urban stormwater planning
Full text linkKlimaendringar og urbanisering fører til at eksisterande dreneringssystem blir utilstrekkelege, noko som vidare leier til ein auka frekvens av urbane flaumar. State of the art for handtering av slike utfordringar består verden over i dag av å bruke såkalla berekraftige urbane dreneringssystem, eller Sustainable Urban Drainage Systems (SUDS). Implementeringa av slike løysingar har derimot vist seg å vere problematisk ettersom overvann- ingeniørar typisk blir innlemma i byggeprosessen for seint til å ha innverknad på det fysiske oppsettet av tomta. I denne oppgåva ser vi på ei ny, numerisk tilnærming til tidleg inkludering av dreneringssystem i slike byggeprosjekt.
Nøkkelfaktorar for ytingsgrada til SUDS vart identifisert gjennom eit litteraturstudie. Desse faktorane vart så brukt til å utvikle eit skoringssystem basert på eit mål om å oppretthalde naturlege tilstandar. Ei optimaliseringsrutine vart vidare utvikla med mål om å oppnå høgast mogleg skoring. Denne optimaliseringa vart skriven i Python- kode for å oppnå best moglege SUDS- konfigurasjonar. Elleve ulike bygningsforslag for eit fiktivt byggeprosjekt på ei verkeleg tomt i Oslo, Noreg, vart romleg analysert. Deretter vart SUDS plassert for kvart enkelt bygningsforslag gjennom bruk av optimeringsskriptet.
Resultata viser først og fremst ein betydeleg forskjell i SUDS- potensiale for dei ulike bygningsforslaga for tomta, med eit stort spenn i flaumhandteringspotensiale. Dette impliserer at SUDS er svært kontekstavhengige. For det andre viser resultata at med ei enkel kode kan ein på effektivt vis analysere mengder av bygningsforslag og/eller SUDS konfigurasjonar. Dette viser eit stort potensiale for å inkludere desse analysane tidleg i eit byggeprosjekt.
Behovet for å inkludere SUDS tidleg i urban planlegging er tydeleg. Det er avgjerande for å sikre at SUDS yter den sårt trengte robustleiken dei har bevist å kunne sikre. Gjennom denne oppgåva har eit første steg mot denne sikringa vorte tatt.Climate change and urbanisation is to a large extent causing the drainage systems to be insufficient which in turn leads to increased flooding in urban areas. The state of the art worldwide today to alleviate such flooding consists in using sustainable urban drainage systems (SUDS). Implementing such solutions proves, however, problematic, since the water management engineers typically enter the building process too late to influence the physical layout of major projects. In this paper, we examine a novel, numerical approach to early inclusion of drainage systems in such projects.
Key factors for the efficiency of SUDS were identified through a literature review. These were used to develop a scoring system based on providing relative proximity to natural conditions. An optimisation routine was then developed with the objective of obtaining the highest possible score. The optimisation routine was scripted in python to obtain the best possible SUDS configurations. Eleven different building proposals for a fictitious development project on a real-life site in Oslo, Norway, were spatially analysed. SUDS were subsequently placed for each building proposal by using the optimising script.
First and foremost, the results showed a significant variation in the potential for SUDS implementations for the different building proposals, ranging from little to considerable flood reduction. This implies that SUDS are highly context dependent. Secondly, the results show great potential to analyse a large number of building proposals and SUDS figuration quite efficiently through a simple script. This implies the applicability of such analysis early in development projects.
The need to include SUDS in early urban planning seems clear. It is paramount in order to ensure that SUDS serve the much-needed resilience they have proved to provide. Through this research, a first step towards ensuring this has been made
Climate-Informed Planning and Design of Urban Water Systems
No full textGlobal warming is expected to cause alterations of the climate with potential impacts on urban water systems. As the knowledge base on climate change expands, and regional climate projections become increasingly available to local water managers, the need for climate-informed tools and decision-support systems rises.
This thesis seeks to address local stakeholders needs for novel tools and frameworks for facilitating climate adaptation and to investigate how climate projections can inform the analyses. The work of this thesis has been conducted as part of the H2020 project BINGO
- Bringing INnovation to onGOing water management - a better future under climate change (Grant Agreement number 641739), where the principal goal has been to provide end-users in the water sector with practical tools and knowledge on climate change.
The thesis specifically attends to three main applications of urban water systems: 1) drinking water availability planning, 2) storm water infrastructure design, and 3) urban drainage systems planning. To support the overall aims of the thesis, the following objectives were defined:
1. Investigate local climate projections and their potential to provide decision-support in local climate adaptation
2. Evaluate climate projections’ applicability for design in current stormwater management practice in Norway
3. Develop climate-informed adaptation frameworks for Norwegian urban water systems
To pursue these objectives, a collection of regional climate projections for the city of Bergen, Norway, was produced, processed and assessed through various tools and techniques. This resulted in a rich ensemble of climate projections for the city, covering a range of emissions scenarios, parent global climate models, and downscaling methods. These projections have further been used as input to hydrologic and hydraulic models embraced by the three defined water sector applications. Through this, the application of climate projections in planning and design of urban water systems was demonstrated and assessed, and frameworks providing decision-support were proposed.
The assessment of the resulting climate projection ensemble emphasizes the general consensus in research that ensemble approaches are necessary to gain a holistic and reliable indication of future local climates, as choices of emissions scenario, parent GCM, predictor, and downscaling techniques all introduce their own range of uncertainty. This implies that climate projections should not be further applied in a traditional predict-then-act manner, but rather treated as what they are: possible scenarios of future climate, sooner than predictions, and ensembles rather than singular best-guess estimates.
To emerge at climate-informed design practices in Norway, the results of this thesis strongly suggest that existing tools and methods should be adjusted to handle a range of input scenarios rather than single event or time series inputs. This would allow a shift from prediction-based design, to a risk-oriented design of urban water systems and system components.
Finally, three main decision-support frameworks are proposed for climate adaptation in the water sector. The three frameworks incorporate a new dimension of climate change information into traditional tools known to the water sector. In addition to addressing the third, and last objective of this thesis, they also contribute to the principle goal of the BINGO project: to provide end-users in the water sector with practical tools and knowledge on climate change. Although the results are site specific, linking frameworks to existing tools ensures scalability and transferability of methodologies
Assessing the robustness of raingardens under climate change using SDSM and temporal downscaling
No full textClimate change is expected to lead to higher precipitation amounts and intensities. This study was carried out to (1) estimate the future precipitation extremes in Bergen (Norway) and (2) assess the robustness of raingardens as stormwater peak flow measures.
A combined spatial temporal downscaling method using the Statistical DownScaling Model-Decision Centric (SDSM-DC) and the Generalized Extreme Value (GEV) distribution was applied to estimate future precipitation. Raingarden performance was simulated with the modelling tool RECARGA.
The method gave results similar to multiplying with a climate factor as recommended by Norsk klimaservicesenter (2016). Uncertainties were found to be higher from temporal rather than spatial downscaling. The method is best suited as a tool for demonstrating possible climate change scenarios, and stress testing systems of interest. The robustness of raingardens as stormwater peak flow measures was found to be highly dependent on saturated hydraulic conductivity (Ksat). The results obtained indicate that a higher Ksat is beneficial for reducing overflow and increasing lag time. However, a lower Ksat value achieves the highest peak flow reductions.
According to the research, a higher Ksat than what is earlier recommended for cold climates is needed to make raingardens robust under climate change
Assessing the robustness of raingardens under climate change using SDSM and temporal downscaling
Full text linkClimate change is expected to lead to higher precipitation amounts and intensities. This study was carried out to (1) estimate the future precipitation extremes in Bergen (Norway) and (2) assess the robustness of raingardens as stormwater peak flow measures.
A combined spatial temporal downscaling method using the Statistical DownScaling Model-Decision Centric (SDSM-DC) and the Generalized Extreme Value (GEV) distribution was applied to estimate future precipitation. Raingarden performance was simulated with the modelling tool RECARGA.
The method gave results similar to multiplying with a climate factor as recommended by Norsk klimaservicesenter (2016). Uncertainties were found to be higher from temporal rather than spatial downscaling. The method is best suited as a tool for demonstrating possible climate change scenarios, and stress testing systems of interest. The robustness of raingardens as stormwater peak flow measures was found to be highly dependent on saturated hydraulic conductivity (Ksat). The results obtained indicate that a higher Ksat is beneficial for reducing overflow and increasing lag time. However, a lower Ksat value achieves the highest peak flow reductions.
According to the research, a higher Ksat than what is earlier recommended for cold climates is needed to make raingardens robust under climate change
Digitalising optimisation of early phase urban stormwater planning
No full textKlimaendringar og urbanisering fører til at eksisterande dreneringssystem blir utilstrekkelege, noko som vidare leier til ein auka frekvens av urbane flaumar. State of the art for handtering av slike utfordringar består verden over i dag av å bruke såkalla berekraftige urbane dreneringssystem, eller Sustainable Urban Drainage Systems (SUDS). Implementeringa av slike løysingar har derimot vist seg å vere problematisk ettersom overvann- ingeniørar typisk blir innlemma i byggeprosessen for seint til å ha innverknad på det fysiske oppsettet av tomta. I denne oppgåva ser vi på ei ny, numerisk tilnærming til tidleg inkludering av dreneringssystem i slike byggeprosjekt.
Nøkkelfaktorar for ytingsgrada til SUDS vart identifisert gjennom eit litteraturstudie. Desse faktorane vart så brukt til å utvikle eit skoringssystem basert på eit mål om å oppretthalde naturlege tilstandar. Ei optimaliseringsrutine vart vidare utvikla med mål om å oppnå høgast mogleg skoring. Denne optimaliseringa vart skriven i Python- kode for å oppnå best moglege SUDS- konfigurasjonar. Elleve ulike bygningsforslag for eit fiktivt byggeprosjekt på ei verkeleg tomt i Oslo, Noreg, vart romleg analysert. Deretter vart SUDS plassert for kvart enkelt bygningsforslag gjennom bruk av optimeringsskriptet.
Resultata viser først og fremst ein betydeleg forskjell i SUDS- potensiale for dei ulike bygningsforslaga for tomta, med eit stort spenn i flaumhandteringspotensiale. Dette impliserer at SUDS er svært kontekstavhengige. For det andre viser resultata at med ei enkel kode kan ein på effektivt vis analysere mengder av bygningsforslag og/eller SUDS konfigurasjonar. Dette viser eit stort potensiale for å inkludere desse analysane tidleg i eit byggeprosjekt.
Behovet for å inkludere SUDS tidleg i urban planlegging er tydeleg. Det er avgjerande for å sikre at SUDS yter den sårt trengte robustleiken dei har bevist å kunne sikre. Gjennom denne oppgåva har eit første steg mot denne sikringa vorte tatt
Assessing the hydraulic performance of a combined sewer system under climate change using temporal downscaling
Full text linkIn recent years, climate change has lead to an increasing number of high intensity rain events causing flooding in urban areas around the world. Studies of different future climate scenarios indicate that this increase will continue both in intensity and frequency. This study was carried out to create future IDF estimates for precipitation extremes in Trondheim, Norway, and to evaluate the hydraulic performance of the combined sewer system in Lerkendal drainage zone in Trondheim under climate change.
Temporal downscaling of spatially downscaled daily AM values from Global Circulation Models (GCMs) using the scaling concept and the Gumbel distribution was applied in the study. The hydraulic performance of the combined Sewer system was assessed using the modelling tool MIKE Urban.
The results from the downscaling, for the highest precipitation intensity increase, corresponded with using a climate factor of 1.4, which also is recommended by the Norwegian Centre for Climate Services to be used in dimensioning of drainage systems in the area. The results from the simulations indicated that the hydraulic capacity of the sewer system is insufficient, and that measures have to be done in the zone for adapting to the future climatic changes. The method applied in the study is easy to implement and would be beneficial for testing the performance of drainage systems under different climate change scenarios, to be a part of a risk analysis, and to inform decisions made in the planning and dimensioning of sewer systems
Assessing the hydraulic performance of a combined sewer system under climate change using temporal downscaling
No full textIn recent years, climate change has lead to an increasing number of high intensity rain events causing flooding in urban areas around the world. Studies of different future climate scenarios indicate that this increase will continue both in intensity and frequency. This study was carried out to create future IDF estimates for precipitation extremes in Trondheim, Norway, and to evaluate the hydraulic performance of the combined sewer system in Lerkendal drainage zone in Trondheim under climate change.
Temporal downscaling of spatially downscaled daily AM values from Global Circulation Models (GCMs) using the scaling concept and the Gumbel distribution was applied in the study. The hydraulic performance of the combined Sewer system was assessed using the modelling tool MIKE Urban.
The results from the downscaling, for the highest precipitation intensity increase, corresponded with using a climate factor of 1.4, which also is recommended by the Norwegian Centre for Climate Services to be used in dimensioning of drainage systems in the area. The results from the simulations indicated that the hydraulic capacity of the sewer system is insufficient, and that measures have to be done in the zone for adapting to the future climatic changes. The method applied in the study is easy to implement and would be beneficial for testing the performance of drainage systems under different climate change scenarios, to be a part of a risk analysis, and to inform decisions made in the planning and dimensioning of sewer systems
Hydrological Assessment of Water Resources in Bergen - Climate Change Impacts
No full textBergen Waterworks is reliant on steady loads of precipitation to meet the drink- ing water demand. Accordingly, the system is vulnerable to drought events and seasonal changes in inflow. Climate change impact analysis, as part of water management design and operation, is advantageous for ensuring a reliable and economic development of the infrastructure. Consequently, adaptation strategies in terms of hydrological assessments ought to keep up with the scientific progress in climate research. This thesis provides a complete framework for evaluating cli- mate change impacts on drinking water resources in Bergen. A comprehensive hydrological assessment is conducted, including inflow data analysis, calibration of regional HBV model, and transferring of calibrated parameters to ungauged catchments. Projected changes in temperature and precipitation are obtained us- ing empirical-statistical downscaling of the global climate model, Nor-ESM1-M, and IPCC AR5 emission scenarios RCP2.6, RCP4.5 and RCP8.5. Climate change impacts are evaluated by comparing historical climate variables for the control pe- riod 1981-2010, with future projections for 2011-2040, 2041-2070 and 2071-2100. Changes in water supply capacity in Bergen are estimated using extreme drought event analysis and hydrological routing. The maximum supply capacity, while accounting for 100 % storage reliability, is confronted with projected changes in drinking water demand. The results convey seasonally inflow changes, connected to changes in the snow regime and increased evapotranspiration. More inflow is expected during winter and autumn, while less is expected in spring and sum- mer. Winter drought extremes are therefore likely to disappear, as opposed to summer drought extremes, for which an upturn is predicted. Within the time span of 2011-2100, all emissions scenarios reduce the maximum supply capacity of Bergen Waterworks. However, neither of the scenarios threaten the reliability of the drinking water supply, provided that leakages in the distribution system are reduced to 20 %
Hydrological Assessment of Water Resources in Bergen - Climate Change Impacts
Full text linkBergen Waterworks is reliant on steady loads of precipitation to meet the drink- ing water demand. Accordingly, the system is vulnerable to drought events and seasonal changes in inflow. Climate change impact analysis, as part of water management design and operation, is advantageous for ensuring a reliable and economic development of the infrastructure. Consequently, adaptation strategies in terms of hydrological assessments ought to keep up with the scientific progress in climate research. This thesis provides a complete framework for evaluating cli- mate change impacts on drinking water resources in Bergen. A comprehensive hydrological assessment is conducted, including inflow data analysis, calibration of regional HBV model, and transferring of calibrated parameters to ungauged catchments. Projected changes in temperature and precipitation are obtained us- ing empirical-statistical downscaling of the global climate model, Nor-ESM1-M, and IPCC AR5 emission scenarios RCP2.6, RCP4.5 and RCP8.5. Climate change impacts are evaluated by comparing historical climate variables for the control pe- riod 1981-2010, with future projections for 2011-2040, 2041-2070 and 2071-2100. Changes in water supply capacity in Bergen are estimated using extreme drought event analysis and hydrological routing. The maximum supply capacity, while accounting for 100 % storage reliability, is confronted with projected changes in drinking water demand. The results convey seasonally inflow changes, connected to changes in the snow regime and increased evapotranspiration. More inflow is expected during winter and autumn, while less is expected in spring and sum- mer. Winter drought extremes are therefore likely to disappear, as opposed to summer drought extremes, for which an upturn is predicted. Within the time span of 2011-2100, all emissions scenarios reduce the maximum supply capacity of Bergen Waterworks. However, neither of the scenarios threaten the reliability of the drinking water supply, provided that leakages in the distribution system are reduced to 20 %
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