Staged cost optimization of urban storm drainage systems based on hydraulic performance in a changing environment

International audienceUrban flooding causes large economic losses, property damage and loss of lives. The impact of environmental changes mainly, the urbanization and the climatic change leads to increased runoff and increased peak flows which the drainage system must be able to cope with to overcome possible damage and inconveniences caused by the induced flooding. Allowing for detention storage to compliment the capacity of the drainage system network is one of the approaches to reduce urban floods. The traditional practice was to design systems against stationary environmental forcings ? including design rainfall, landuse, etc. Due to the rapid change in climate-environment, this approach is no longer economically viable and safe, and explicit consideration of changes that gradually take place during the life-time of the drainage system is warranted. In this paper, a staged cost optimization tool based on the hydraulic performance of the drainage system is presented. A one dimensional hydraulic model is used for hydraulic evaluation of the network together with a genetic algorithm based optimization tool to determine optimal intervention timings and amounts throughout the lifespan of the drainage network. The model was applied in a case study area in the city of Porto Alegre, Brazil. It was concluded that considerable financial savings and/or additional level of flood-safety can be achieved by approaching the design problem as a staged plan rather than one-off scheme

Informing UK governance of resilience to climate risks: improving the local evidence-base

International assessments of evidence on climate change (e.g. Intergovernmental Panel on Climate Change, IPCC) or national climate change risk assessments (e.g. UK Climate Change Risk Assessment, CCRA) do not offer a sufficiently granular perspective on climate impacts to adequately inform governance of resilience to climate risks at the local level. Using an analysis of UK decision-makers managing and responding to heatwaves and flood risks, this paper argues how more robust local evidence is needed to inform decision-making regarding adaptation options for enhancing local resilience. We identify evidence gaps and issues relating to local climate change impacts, including sources and quality of evidence used, adequacy and accessibility of evidence available, ill-communicated evidence and conflicting or misused evidence. A lack of appreciation regarding how scientific evidence and personal judgement can mutually enhance the quality of decision-making underpins all of these gaps. Additionally, we find that the majority of evidence currently used is reductively based upon socio-economic and physical characteristics of climate risks. We argue that a step change is needed in local climate resilience that moves beyond current physical and socio-economic risk characterisation to a more inclusive co-constitution of social and politically defined climate risks at the local scale that are better aligned with the local impacts felt and needs of stakeholders

The resilience approach to climate adaptation applied for flood risk; Dissertation, UNESCO-IHE Institute for Water Education, Delft.

The uncertainties associated with making investment decisions for flood risk management can be significant and arise from, amongst other factors, a lack of knowledge about external drivers, like climate change. These uncertainties make it necessary to succeed the (quasi-)stationarity approach for the development of investment strategies. Otherwise, such strategies can be maladaptive, resulting in e.g. unnecessary costs of potentially irreversible measures. This dissertation presents a potential way forward for adaptation to climate change, termed the resilience approach. The resilience approach takes a dynamic perspective on adaptive processes and the effects of these processes at/across different spatio-temporal scales. The methods required for applying the resilience approach should give insight into and promote the ability of a system to deal with future change. This comprises the ability not only to respond to change as a threat, but also to take advantage of opportunities that arise from future change. Case study experience is provided with four methods: Adaptive Policy Making, Real-In-Options, Adaptation Tipping Points and - Adaptation Mainstreaming Opportunities. This dissertation discusses the concept, procedure and benefits/limitations of each method, examining its usefulness for informing investment decisions for flood risk management. It gives specific recommendations on which method to use under what circumstances

The resilience approach to climate adaptation applied for flood risk

This dissertation presents a potential way forward for adaptation to climate change, termed the resilience approach. This approach takes a dynamic perspective on adaptive processes and the effects of these processes at/across different spatio-temporal scales. Experience is provided with four methods that can be used to apply the resilience approach: Adaptive Policy Making, Real-In-Options, Adaptation Tipping Points and - Adaptation Mainstreaming Opportunities. This dissertation discusses the concept, procedure and benefits/limitations of each method, examining its usefulness for informing investment decisions for flood risk management. It also gives specific recommendations on which method to use under what circumstances.Hydraulic EngineeringCivil Engineering and Geoscience

Implementatie meerlaagsveiligheid in Nederland: realisatie plannen vergt institutionele verandering

Contains fulltext : 121956.pdf (publisher's version ) (Open Access

Web 2.0 collaboration tool to support student research in hydrology - an opinion

A growing body of evidence suggests that it is unwise to make the a-priori assumption that university students are ready and eager to embrace modern online technologies employed to enhance the educational experience. We present our opinion on employing Wiki, a popular Web 2.0 technology, in small student groups, based on a case-study of using it customized to work as a personal learning environment (PLE1) (Fiedler and Väljataga, 2011) for supporting thesis research in hydrology. Since inception in 2006, the system presented has proven to facilitate knowledge construction and peer-communication within and across groups of students of different academic years and to stimulate learning. Being an open ended and egalitarian system, it was a minimal burden to maintain, as all students became content authors and shared responsibility. A number of unintended uses of the system were also observed, like using it as a backup medium and mobile storage. We attribute the success and sustainability of the proposed Web 2.0-based approach to the fact that the efforts were not limited to the application of the technology, but comprised the creation of a supporting environment with educational activities organized around it. We propose that Wiki-based PLEs are much more suitable than traditional learning management systems for supporting non-classroom education activities like thesis research in hydrology

Towards Sustainable Planning and Design of Stormwater Control Solutions in Brazil

Brazil is currently facing widespread problems in the urban environment associated with inadequate systems for drainage of urban stormwater runoff. The PNSB study (2000) identified that out of a total of 5507 municipalities 22% suffered from flooding in the 1998- 1999 period. The majority of problems occurred in the southern states, which have higher rates of urbanisation and higher amounts of rainfall. The problems of urban drainage are compounded by a lack of public awareness and participation, insufficient funds to supply and maintain the basics of sanitation and drainage, weak municipal organisations and a lack of coordination between the different organisations. Traditional master planning has generally failed to address the problems adequately and the implementation of these plans has tended to rely on large-scale costly infrastructure projects, which in some instances have attributed to the worsening of problems, as the stormwater is drained rapidly resulting in the exacerbation of downstream flooding. As a result of the inadequacies of traditional responses, combined with increasing awareness of the need for integrated approaches, a new generation of management plans for urban drainage is emerging. Urban drainage management In recent years some regional capitals have developed an Urban Drainage Master Plan together with appropriate legislation, starting from the premise that newly urbanised spaces should not increase natural surface runoff and that urban drainage must be integrated with planning the urban environment of cities. Experience with the development of Urban Drainage Master Plans showed that institutional and strategic/communicational aspects are essential for the success of the plan and thus deserve special attention. The plan development process in the city of Porto Alegre is a relevant example of that process. This is the main consideration to select the Urban Drainage Master Plan of Porto Alegre as the case study for this master thesis. Using an assessment framework, focusing on relevant criteria concerning both content and process, this study presents an overview of the policy cycle in Porto Alegre, with a focus on the shortcomings and strongpoints of the followed approach in relation to the concept of sustainable development. The objective of this study The overall objective of the study is to improve the approaches for the planning and design of stormwater control solutions in Brazil. From the case study several analyses are possible, which can help to improve the approaches in Porto Alegre and other Brazilian cities. As a first step, critical factors for the success of the plan are identified according to the information and insights that came to light on the basis of the assessment criteria (concept, scope, and knowledge).Transport & PlanningCivil Engineering and Geoscience

The identity approach for assessing socio-technical resilience to climate change: Example of flood risk management for the Island of Dordrecht

Recent EU guidance on adaptation calls for the enhancement ofsocio-technical resilience to climate change. However, socio-technical resilience is relatively poorly defined and this makes it difficult to apply in practice. This paper uses the concept of identity as a vehicle to advance the definition and assessment of socio-technical resilience. Identity comprises four aspects (components, relationships, innovation, and continuity) that constitute the minimum of what has to be identified and specified if resilience is to be assessed. Characterising the identity ofa socio-technical system requires the conceptualisation of these four aspects in relation to the particular function provided by the system (e.g. flood risk management) and also the identification of the specific variables and thresholds that reflect changes in identity. We have demonstrated the utility of the identity approach, using the example of flood risk management for the Island of Dordrecht, the Netherlands. Based on the results, socio-technical resilience has been redefined as the ability of the system to continue to function as expected in the face of change. This definition implies that a system is resilient when it can deliver performance without a change ofidentity by continuing compliance with standards and expectations