Assessment of Urban Water Infrastructure System Resilience

Urban water infrastructure systems are exposed to the impacts of various chronic and acute stressors such as climate change, population growth/decline, aging infrastructure, and extreme events (e.g., natural disasters). The ability and capacity of infrastructure systems to cope with the impacts of these stressors is characterized as resilience. Water utility agencies and infrastructure managers face significant challenges (due to deep uncertainty, funding constraints, lack of knowledge, etc.) to enhance the long-term resilience of their urban water infrastructure systems under the impacts of external stressors. To enable informed resilience planning and adaptation decisions, the present study adopted a complex system perspective to comprehensively assess the long-term resilience of water infrastructure systems. Through this perspective, different components of the complex water infrastructure system (i.e., physical infrastructures, human actors, external stressors) were captured, modeled, and analyzed using a simulation approach for theory development and exploratory assessment. This research conducted four interrelated studies focused on both supply and demand sides of the water infrastructure resilience. As aging water distribution infrastructures near the end of their useful lifespan, first two studies focused on the resilience of water distribution systems. The first study established a framework to understand the long-term resilience of water distribution infrastructure systems based on performance regimes and tipping point behaviors under various scenarios of renewal strategies, funding levels, and population changes. The second study, examined the long-term performance of dual water distribution networks, as an alternative infrastructure solution proposed for improving the resilience of water distribution systems, in comparison with the conventional singular networks. The third study was prompted to deal with the impacts of climate change on coastal water supply infrastructures. This study specifically, evaluated the influence of adaptation decision-making processes of utility agencies on the long-term resilience of water supply systems under the impacts of sea-level rise and saltwater intrusion. Finally, the fourth study focused on the evaluation of demand-side solutions to enhance the resilience of urban water infrastructure systems, where due to population growth, climate change, and other factors making water scarcer, the supply-side solutions may no longer be sufficient. The last study particularly analyzed the underlying mechanisms affecting the adoption of water conservation technology by households to uncover the potential for residential water demand reduction. Accordingly, four sets of important theoretical constructs related to long-term resilience of water infrastructure systems were identified from the analysis of simulated data: (i) the long-term performance regime of water distribution infrastructure system is shaped by its internal dynamics related to stressors-humans-infrastructure interactions; (ii) implementation of dual water distribution systems would improve the long-term performance (by decreasing water loss and energy loss by 28% and 80%, respectively) but with three times higher life-cycle costs; (iii) the state of nature (i.e., sea-level rise severity) is the most important determinant of coastal water supply infrastructure system resilience, regardless of the attributes of adaptation decisions; and (iv) households’ decision regarding the adoption of water conservation technology is driven mostly by income level and water pricing structure. The simulation results highlighted the importance and capabilities of the proposed frameworks in better understanding of water supply infrastructure system resilience. The insights of this research would also benefit water utilities, city planners, municipalities, and other stakeholders endeavoring to strengthen the resilience performance of water infrastructure systems. Progress in this domain improves the overall resilience of communities’ infrastructure systems to normal wear-and-tear and natural disasters alike

Understanding Fundamental Phenomena Affecting the Water Conservation Technology Adoption of Residential Consumers Using Agent-Based Modeling

More than one billion people will face water scarcity within the next ten years due to climate change and unsustainable water usage, and this number is only expected to grow exponentially in the future. At current water use rates, supply-side demand management is no longer an effective way to combat water scarcity. Instead, many municipalities and water agencies are looking to demand-side solutions to prevent major water loss. While changing conservation behavior is one demand-based strategy, there is a growing movement toward the adoption of water conservation technology as a way to solve water resource depletion. Installing technology into one’s household requires additional costs and motivation, creating a gap between the overall potential households that could adopt this technology, and how many actually do. This study identified and modeled a variety of demographic and household characteristics, social network influence, and external factors such as water price and rebate policy to see their effect on residential water conservation technology adoption. Using Agent-based Modeling and data obtained from the City of Miami Beach, the coupled effects of these factors were evaluated to examine the effectiveness of different pathways towards the adoption of more water conservation technologies. The results showed that income growth and water pricing structure, more so than any of the demographic or building characteristics, impacted household adoption of water conservation technologies. The results also revealed that the effectiveness of rebate programs depends on conservation technology cost and the affluence of the community. Rebate allocation did influence expensive technology adoption, with the potential to increase the adoption rate by 50%. Additionally, social network connections were shown to have an impact on the rate of adoption independent of price strategy or rebate status. These findings will lead the way for municipalities and other water agencies to more strategically implement interventions to encourage household technology adoption based on the characteristics of their communities

Resilience as an emergent property of human-infrastructure dynamics: A multi-agent simulation model for characterizing regime shifts and tipping point behaviors in infrastructure systems.

The objective of this study is to establish a framework for analyzing infrastructure dynamics affecting the long-term steady state, and hence resilience in civil infrastructure systems. To this end, a multi-agent simulation model was created to capture important phenomena affecting the dynamics of coupled human-infrastructure systems and model the long-term performance regimes of infrastructure. The proposed framework captures the following three factors that shape the dynamics of coupled human-infrastructure systems: (i) engineered physical infrastructure; (ii) human actors; and (iii) chronic and acute stressors. A complex system approach was adopted to examine the long-term resilience of infrastructure based on the understanding of performance regimes, as well as tipping points at which shifts in the performance regime of infrastructure occur under the impact of external stressors and/or change in internal dynamics. The application of the proposed framework is demonstrated in a case of urban water distribution infrastructure using the data from a numerical case study network. The developed multi-agent simulation model was then used in examining the system resilience over a 100-year horizon under stressors such as population change and funding constraints. The results identified the effects of internal dynamics and external stressors on the resilience landscape of infrastructure systems. Furthermore, the results also showed the capability of the framework in capturing and simulating the underlying mechanisms affecting human-infrastructure dynamics, as well as long-term regime shifts and tipping point behaviors. Therefore, the integrated framework proposed in this paper enables building complex system-based theories for a more advanced understanding of civil infrastructure resilience

Water Distribution Infrastructure Model

This data includes the source code for a simulation model of urban water distribution infrastructure system developed to integrate the institutional agencies’ renewal decision-making processes with physical components in order to simulate the transformations and capture the dynamics of water distribution infrastructure under external stressors such as population change and funding fluctuations. Using the developed simulation model, various experiments can be designed to measure the long-term resilience based on the visual detection of regime shifts and identification of the threshold values (i.e., tipping points) associated with infrastructure performance regimes

Model Source Codes for: Resilience Planning in Hazards-Humans-Infrastructure Nexus: A Multi-agent Simulation for Exploratory Assessment of Coastal Water Supply Infrastructure Adaptation to Sea-level Rise

The simulation model has been uploaded in an open repository (AnyLogic Cloud), where it can be implemented online. The Java codes of the developed simulation model can be found in this document.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Comparative evaluation of the performance of an improved biomass cook stove and the traditional stoves of Iran

In international development programs on improvement of energy supply for cooking in remote regions, biomass gasifier cook stoves have a remarkable place. Fuel type and size play a key role on the performance of such stoves. The most abundant woody biomass waste in Iran is apple pruning waste (up to 1.32 Mt a year). This paper reports the result of evaluation of a top lit updraft biomass stove specifically modified to burn apple pruning waste. In addition, the improved biomass cooking stove (ICS) was technically compared with traditional cook stove (TCS) based on Water Boiling Test 4.2.3 and time to boil (TTB) instruction. Water and flame temperature variations were compared with a natural gas stove (GS), as the most common cooking device in Iran. The average TTB was 12, 13, and 20 min for the GS, ICS, and TCS, respectively. The comparison of regression equations indicated that the rate of increase in the flame and water temperature in the both ICS and GS were similar. In general, better thermal efficiency was observed in the ICS (about 35%) in comparison with the TCS (12.6%). The specific and the total fuel consumption in the ICS were 73 and 67% lower than that of the TCS, respectively. Keywords: Biomass waste, Thermal efficiency, Firewood, Regression mode

Tracing app technology: an ethical review in the COVID-19 era and directions for post-COVID-19

We conducted a systematic literature review on the ethical considerations of the use of contact tracing app technology, which was extensively implemented during the COVID-19 pandemic. The rapid and extensive use of this technology during the COVID-19 pandemic, while benefting the public well-being by providing information about people’s mobility and movements to control the spread of the virus, raised several ethical concerns for the post-COVID-19 era. To investigate these concerns for the post-pandemic situation and provide direction for future events, we analyzed the current ethical frameworks, research, and case studies about the ethical usage of tracing app technology. The results suggest there are seven essential ethical considerations—privacy, security, acceptability, government surveillance, transparency, justice, and voluntariness—in the ethical use of contact tracing technology. In this paper, we explain and discuss these considerations and how they are needed for the ethical usage of this technology. The fndings also highlight the importance of developing integrated guidelines and frameworks for implementation of such technology in the post- COVID-19 world