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Research papers, University of Canterbury Library

Sewerage systems convey sewage, or wastewater, from residential or commercial buildings through complex reticulation networks to treatment plants. During seismic events both transient ground motion and permanent ground deformation can induce physical damage to sewerage system components, limiting or impeding the operability of the whole system. The malfunction of municipal sewerage systems can result in the pollution of nearby waterways through discharge of untreated sewage, pose a public health threat by preventing the use of appropriate sanitation facilities, and cause serious inconvenience for rescuers and residents. Christchurch, the second largest city in New Zealand, was seriously affected by the Canterbury Earthquake Sequence (CES) in 2010-2011. The CES imposed widespread damage to the Christchurch sewerage system (CSS), causing a significant loss of functionality and serviceability to the system. The Christchurch City Council (CCC) relied heavily on temporary sewerage services for several months following the CES. The temporary services were supported by use of chemical and portable toilets to supplement the damaged wastewater system. The rebuild delivery agency -Stronger Christchurch Infrastructure Rebuild Team (SCIRT) was created to be responsible for repair of 85 % of the damaged horizontal infrastructure (i.e., water, wastewater, stormwater systems, and roads) in Christchurch. Numerous initiatives to create platforms/tools aiming to, on the one hand, support the understanding, management and mitigation of seismic risk for infrastructure prior to disasters, and on the other hand, to support the decision-making for post-disaster reconstruction and recovery, have been promoted worldwide. Despite this, the CES in New Zealand highlighted that none of the existing platforms/tools are either accessible and/or readable or usable by emergency managers and decision makers for restoring the CSS. Furthermore, the majority of existing tools have a sole focus on the engineering perspective, while the holistic process of formulating recovery decisions is based on system-wide approach, where a variety of factors in addition to technical considerations are involved. Lastly, there is a paucity of studies focused on the tools and frameworks for supporting decision-making specifically on sewerage system restoration after earthquakes. This thesis develops a decision support framework for sewerage pipe and system restoration after earthquakes, building on the experience and learning of the organisations involved in recovering the CSS following the CES in 2010-2011. The proposed decision support framework includes three modules: 1) Physical Damage Module (PDM); 2) Functional Impact Module (FIM); 3) Pipeline Restoration Module (PRM). The PDM provides seismic fragility matrices and functions for sewer gravity and pressure pipelines for predicting earthquake-induced physical damage, categorised by pipe materials and liquefaction zones. The FIM demonstrates a set of performance indicators that are categorised in five domains: structural, hydraulic, environmental, social and economic domains. These performance indicators are used to assess loss of wastewater system service and the induced functional impacts in three different phases: emergency response, short-term recovery and long-term restoration. Based on the knowledge of the physical and functional status-quo of the sewerage systems post-earthquake captured through the PDM and FIM, the PRM estimates restoration time of sewer networks by use of restoration models developed using a Random Forest technique and graphically represented in terms of restoration curves. The development of a decision support framework for sewer recovery after earthquakes enables decision makers to assess physical damage, evaluate functional impacts relating to hydraulic, environmental, structural, economic and social contexts, and to predict restoration time of sewerage systems. Furthermore, the decision support framework can be potentially employed to underpin system maintenance and upgrade by guiding system rehabilitation and to monitor system behaviours during business-as-usual time. In conjunction with expert judgement and best practices, this framework can be moreover applied to assist asset managers in targeting the inclusion of system resilience as part of asset maintenance programmes.

Videos, UC QuakeStudies

A video of a presentation by Richard Conlin during the Community Resilience Stream of the 2016 People in Disasters Conference. The presentation is titled, "Resilience, Poverty, and Seismic Culture".The abstract for this presentation reads as follows: A strategy of resilience is built around the recognition that effective emergency response requires community involvement and mobilization. It further recognizes that many of the characteristics that equip communities to respond most effectively to short term emergencies are also characteristics that build strong communities over the long term. Building resilient communities means integrating our approaches to poverty, community engagement, economic development, and housing into a coherent strategy that empowers community members to engage with each other and with other communities. In this way, resilience becomes a complementary concept to sustainability. This requires an asset-based change strategy where external agencies meet communities where they are, in their own space, and use collective impact approaches to work in partnership. This also requires understanding and assessing poverty, including physical, financial, and social capital in their myriad manifestations. Poverty is not exclusively a matter of class. It is a complex subject, and different communities manifest multiple versions of poverty, which must be respected and understood through the asset-based lens. Resilience is a quality of a community and a system, and develops over time as a result of careful analysis of strengths and vulnerabilities and taking actions to increase competencies and reduce risk situations. Resilience requires maintenance and must be developed in a way that includes practicing continuous improvement and adaptation. The characteristics of a resilient community include both physical qualities and 'soft infrastructure', such as community knowledge, resourcefulness, and overall health. This presentation reviews the experience of some earlier disasters, outlines a working model of how emergency response, resilience, and poverty interact and can be addressed in concert, and concludes with a summary of what the 2010 Chilean earthquake tells us about how a 'seismic culture' can function effectively in communities even when government suffers from unexpected shortcomings.