Resilience Of Water Supply Systems Research Articles

A Quantitative Evaluation Model for the Seismic Resilience of Water Supply Systems Based on Fragility Analysis

A quantitative evaluation model is proposed to assess the seismic resilience of water supply systems. The water supply system is divided into three parts: water sources, aboveground infrastructures, and underground pipeline network, and importance factors for the different parts are quantified. Resilience demand is expressed as the desirable functionality loss and the recovery time of the water supply system after an earthquake. First, seismic fragility models are established for the different components of the water supply system. A water quality index is utilized to represent the impact of earthquakes on the water sources, the seismic performances of aboveground infrastructures are represented by fragility curves, and the repair rate in terms of number of repairs per kilometer is adopted for the pipeline network. Then, the post-earthquake functionality of the water supply system is quantified based on seismic fragility analysis. Changes in the water quality index are used to indicate the functionality losses related to water sources, the functionality losses of aboveground infrastructures are represented by the economic losses derived from component fragility curves, and post-earthquake functionality losses in the underground pipeline network are quantified by hydraulic simulations. The functionalities of the three parts are calculated separately, and then the overall system functionalities are obtained as the sum of the weighted functionalities of the three parts. Finally, a repair strategy is developed and the recovery time is calculated considering the system damage scenarios, system functionality analyses, and resource reserves. The proposed resilience assessment model considers all components of the water supply system, and the results are reliable when the basic information is complete and accurate.

Strategic analysis of the drought resilience of water supply systems

Severe droughts can result in shortages of water supplies, with widespread social and economic consequences. Here we use a coupled simulation model to assess the reliability of public water supplies in England, in the context of changing scenarios of water demand, water regulation and climate change. The coupled simulation model combines climate simulations, a national-scale hydrological model and a national-scale water resource systems model to demonstrate how extreme meteorological droughts translate into hydrological droughts and water shortages for water users. We use this model to explore the effectiveness of strategic water resource options that are being planned in England to secure water supplies to most of England's population up to a drought return period of 1 in 500 years. We conclude that it is possible to achieve a 1-in-500-years standard in locations where strategic resource options are used, while also reducing water abstraction to restore the aquatic environment. However, the target will be easier to achieve if effective steps are also taken to reduce water demand.This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.

A three-staged framework for measuring water supply resilience in rural China based on PLS-SEM

China suffers from frequent large-scale earthquakes, posing a significant challenge to the development and integrity of its rural water supply system (RWSS). The earthquake resilience of water supply systems is understood to be a function of multifaceted factors, which are time- and space-dependent. Measuring the seismic-resilience of RWSS in China remains a challenge. This paper proposes a multi-stage comprehensive evaluation framework, focusing on the relationship between multi-dimensional factors and the seismic- resilience of RWSS in rural areas, across three stages: before, during and after earthquake events. This study comprises four steps: (1) Development of a multi-stage evaluation conceptual framework; (2) identification of seismic-resilience factors; (3) verification of the relationships between factors and stages; and (4) formation of the final evaluation framework. The relationship between multi-dimensional factors is confirmed by a method of triangulation through the quantitative analysis of PLS-SEM combined with the qualitative literature analysis, highlighting the causal approach of the resilience of RWSSs, so as to better understand the resilience state of each stage of disaster. Understanding these factors and their influence on the seismic capacity of RWSS will enable local authorities to recognize the existing advantages and disadvantages of these factors, so as to carry out better resilience practice in all stages of disasters.

Seismic Resilience of Rural Water Supply Systems; Factor Analysis of Cases Set in Sichuan Province, China.

The seismic resilience of water supply systems can be impacted by numerous factors, but what these factors are in the rural context of China is unknown. In this study, 41 potential influencing factors of seismic-resilience for rural water supply system (RWSS) were obtained through a literature review and semi-structured expert interview, comprising 26 general influencing factors (GFs) and 15 water supply safety influencing factors (SFs). This study verified and ranked these factors through a questionnaire survey delivered to RWSS stakeholders in Sichuan Province, China. Based on 123 valid, returned questionnaires, these factors are divided into 9 factor groups through factor analysis performed on GFs and SFs, respectively, of which “economic resilience” and “organizational resilience in disaster prevention stage” are shown to be the most important factor groups. Additionally, it found that the experience of earthquake events significantly affects the perceptions of stakeholders on the importance of certain factors. Specifically, stakeholders who have experienced an earthquake prioritize the post-earthquake resilience of the system, while those who have not experienced an earthquake prioritize the absorption capacity of the system in the disaster prevention stage. Thus, it is not appropriate to use fixed weights to evaluate the seismic resilience of RWSSs. Significantly, this outcome differs from existing findings on the resilience of Urban Water Supply Systems (UWSSs), where “technical resilience” is the key dimension. These findings can help decision-makers fully understand the factors affecting the seismic resilience of RWSSs in China, and in doing so, augment the strengthening of rural water supply.

Combined Management of Groundwater Resources and Water Supply Systems at Basin Scale Under Climate Change

Water stress conditions associated with population growth, climate change, and groundwater contamination, represent a significant challenge for all stakeholders in the water sector. Increasing the resilience of Water Supply Systems (WSSs) becomes of fundamental importance: along with an adequate level of service, sustainability targets must be ensured. A long-term management strategy is strictly connected to a holistic approach, based on analyses at different scales. To this end, both groundwater modeling tools and water management models, with different spatial and temporal scales, are routinely and independently employed. Here, we propose a coupled approach combining: i) groundwater models (MODFLOW) to investigate different stress scenarios, involving climate change and anthropic activities; ii) water management models (Aquator), to assess the water resources availability and the best long-term management strategy for large-scale WSS. The management models are implemented starting from input and output flows derived by groundwater models: this leads to establish a comprehensive framework usually not defined in management models and including a quantitative characterization of the aquifer. The proposed methodology, general and applicable to any study area, is here implemented to the WSS of Reggio Emilia Province, and its main groundwater resource, the Enza aquifer, considering three different stress scenarios for groundwater models (BAU, ST1, and ST2), and for management strategies (BAU, BAURV2, ST2). Among the key results, we observe that coupling the two model types: i) allows evaluating water resources availability in connection with management rules; ii) leads to examining more realistic operation choices; iii) permits planning of infrastructures at basin scale.

Comprehensive Indicator Bank for Resilience of Water Supply Systems

Appropriate indicators are required to measure the resilience of water supply systems (WSSs). However, it is challenging to identify appropriate indicators since there is no comprehensive database of indicators to measure its resiliency. This study will establish a comprehensive bank of indicators to assist water corporations and decision-makers in selecting appropriate indicators for their particular system. The suggested indicator bank is comprised of three layers such as dimension, attributes, and the number of indicators resulting from 12 different indicator codes that the study has analysed. In addition, this paper presents instructions on how the indicator bank can be used and integrated with water enterprises, enabling decision-makers to pick the relevant indicators. The proposed indicator bank is an exploratory approach that should be validated in a real work setting since resilience is a challenging concept, and WSSs are complex due to their dependencies to other lifelines such as power networks with too many variables that may affect the actual outcomes.

Resilience Assessment and Critical Point Identification for Urban Water Supply Systems under Uncertain Scenarios

The urban water supply system environment is becoming more complicated and unpredictable than ever before in the context of global climate change and expanding urbanization. Existing studies have adopted either static or dynamic approaches to assess the resilience of water supply systems without combining the two. Previous literature mostly establishes rigid quantitative metrics for resilience assessment, often without depicting the dynamics and adaptability of system resilience. For example, these studies usually fail to provide a critical point for identifying system resilience. To accurately describe the dynamics and adaptability of water supply system resilience under uncertain scenarios, in this study, we constructed a comprehensive framework based on the qualitative assessment of the input parameters, combining static and dynamic assessment, with the latter playing a dominant role based on the system perspective of pressure–state–influence–response. Taking Qingdao as a case study, we combined this framework with the system resilience theory, and statically assessed the five types of capitals and three attributes of resilience with the capital portfolio approach (CPA). Then, we dynamically assessed the resilience of urban water supply systems and identified critical points with the dynamic socio-technical model coupled with system resilience and the fitting analysis method. The results are as follows: (1) the static assessment results demonstrate an imbalanced development in the levels of the five types of capitals (financial capital, management efficiency, infrastructure, available water resources, and adaptation) and three attributes (robustness, recoverability, and adaptability) in the water supply systems of Qingdao. (2) The dynamic assessment results show that the current resilience trajectory of the water supply systems in Qingdao is that of a city in transition. (3) The fitting analysis shows that robustness (RB) has a linear relationship with resilience, recoverability (RE) has a non-linear relationship with resilience, and the critical points are RB = 0.70 and RE = 1.20. The research findings provide a reference for studying resilience mechanisms, internal attribute relationships, and resilience enhancement measures of urban water supply systems.

Tool development to measure the resilience of water supply systems in Tanzania: Economic dimension.

The world has experienced devastating disasters causing severe human life and economic losses, which is estimated to be 68.5% of the global economic losses between 2005 and 2017. Natural disasters are of great concern – they caused total damage of approximately $3.5 trillion during the past century – which is more than the global infrastructure development investment in 2014. Floods – exacerbated by climate change – are expected to cause more damages, and water supply infrastructures will continue to suffer if resilience is not improved. Measuring the economic changes affecting resilience would assist in developing risk reduction initiatives to minimise disaster losses. Such a measure is lacking for Tanzania water supply systems (WSSs). The current article applied three-stage processes – literature review, pre-assessment and Delphi technique – to develop a resilience tool to measure economic resilience for urban WSSs in Tanzania. Thematic and standard descriptive analyses were carried out during the study. Dynamism principle and three indicators – system investment proportionality, public–private partnership and cost recovery – emerged as principal components for the tool. The tool is expected to be useful during water authorities’ planning processes and budgeting in order to improve the overall WSSs resilience.

Will There Be Enough Water? A System Dynamics Model to Investigate the Effective Use of Limited Resources for Emergency Water Supply

The increased probability of occurrence of various hazards to water supply systems due to climate change requires the strengthening of their resilience through effective emergency preparedness planning. This paper introduces a method for the assessment of the resilience of water supply systems, including emergency supply measures. With 20 uniquely defined emergency situations, the technical constellations for possible impairments of the water supply are documented. The system analysis developed for each emergency situation is then used to determine and prioritise all suitable supply measures to reduce the supply deficit. Based on the data of a water utility close to Frankfurt, Germany, the developed system dynamics model was used to examine the resource utilisation for the respective emergency situations and to estimate the amount of water provided. The model allows us to scrutinize and compare emergency water supply measures as well as to identify required resources. Furthermore, the method helps us to prioritize measures as well as to make decisions when planning and providing emergency water supply (EWS).

Tool development to measure the resilience of water supply systems in Tanzania: Economic dimension

he world has experienced devastating disasters causing severe human life and economic losses, which is estimated to be 68.5% of the global economic losses between 2005 and 2017. Natural disasters are of great concern – they caused total damage of approximately $3.5 trillion during the past century – which is more than the global infrastructure development investment in 2014. Floods – exacerbated by climate change – are expected to cause more damages, and water supply infrastructures will continue to suffer if resilience is not improved. Measuring the economic changes affecting resilience would assist in developing risk reduction initiatives to minimise disaster losses. Such a measure is lacking for Tanzania water supply systems (WSSs). The current article applied three-stage processes – literature review, pre-assessment and Delphi technique – to develop a resilience tool to measure economic resilience for urban WSSs in Tanzania. Thematic and standard descriptive analyses were carried out during the study. Dynamism principle and three indicators – system investment proportionality, public–private partnership and cost recovery – emerged as principal components for the tool. The tool is expected to be useful during water authorities’ planning processes and budgeting in order to improve the overall WSSs resilience.

Development of a Tool for Measuring Resilience of Water Supply Systems in Tanzania: Technical Dimension

AbstractTanzania water supply systems (WSSs) are facing resilience problems, compromising the quality and coverage of water supply services during floods. The expected rise in flood frequency and m...

Economic factors affecting water supply resilience to disasters

Water supply systems need to be resilient enough to provide people and critical users with reliable water following a disaster. Previous research has shown that four main factors dictate system robustness and rapidity of recovery following a disaster: vulnerability, social capital, organisational capacity, and economic capital. This paper identifies the economic factors affecting water supply resilience. Relevant factors and indicators were gathered through a comprehensive literature review and verified through a series of interviews with water supply, resilience, and social scientists and economists. Economic capacity and quick access to finance were found to be the main economic factors influencing the resilience of water supply systems. Quick access to finance is most important in the early stages following a disaster for response and restoration, but its importance declines over time. In contrast, the economic capacity of the disaster struck area as well as the water sector play a vital role in the subsequent reconstruction phase rather than in the response and restoration period. Indicators for these factors were tested for the case of the February 2011 earthquake in Christchurch, New Zealand.

Developing a tool to measure the organizational resilience of Tanzania's water supply systems

Confronted with serious environmental challenges, water supply organizations in Tanzania struggle to prioritize and allocate resources to building resilience to floods so that they can provide uninterrupted service or resume services after a crisis in a timely manner. A study of the key indicators and principles of organizational resilience, combined with input from a panel of water industry experts, led to the development of a tool to gauge organizational resilience that was tested with data from a Tanzanian water authority. Awareness of environmental issues, having an emergency response plan in place, providing staff and the public with opportunities to learn more about building resiliency, clear and ongoing communications, and strong leadership emerged as the most important indicators for measuring the organizational resilience of water supply systems. Encompassing change readiness, leadership and culture, legal frameworks and institutional setup, and networks and relationships, the assessment tool that was developed can guide water authority managers worldwide in developing processes to ensure uninterrupted service to their communities.

From Mosaic to Systemic Redux: The Conceptual Foundation of Resilience and Its Operational Implications for Water Resource Management

Preserving and enhancing the resilience of water supply systems is an important goal for managers to help ensure the ongoing availability of a resource necessary to both economic activity and basic survival. If not explicitly identified as a goal, it can be inferred from the desire to preserve water supply against a variety of stressors for current and future generations. Pursuing resilience is less than straightforward as there are multiple concurrent theoretical paradigms. Furthermore, operationalizing even one of these can be challenging. The authors survey several dominant paradigms with an eye towards distilling the essential, combinative properties of resilience. The contention underwriting this approach is that each paradigm yields important insights about resilience as a complex, emergent system characteristic. This survey lays the foundation for the operationalized approach that is the central thrust of the paper. Specifically, the authors develop an equation based on these properties and identify water resource metrics that correspond to each property. The analysis concludes with a preliminary causal loop diagram intended to capture key system variables and relationships between them. The authors argue that a systemic, conceptually robust approach to resilience is necessary to (1) assess current levels, and (2) improve levels of water resource system resilience.

Sustainability Analysis of Alternative Long-Term Management Strategies for Water Supply Systems: A Case Study in Reggio Emilia (Italy)

Increasing urban water demand and water stress conditions due to population growth, combined with climate change and a non-uniform distribution of water resources in space and time, represent major concerns for water companies. As such, long-term management strategies need to improve the resilience of water supply systems and account for the sustainability of water withdrawals. In this context, metabolic modelling may provide a support to decision-making in the medium-long term, based on sustainability criteria. This approach enables mimicking a water supply network (WSN) based on a set of material and energy fluxes that interact and influence each other. By analyzing these fluxes, a suite of key performance indicators (KPIs) is evaluated in order to identify which kind of interventions may be applied to increase the sustainability of the system. Here, we apply a metabolic model, WaterMet2, to a WSN in the Reggio Emilia Province (Italy), combined with hydraulic simulations conducted with EPANET. Different alternative strategies are compared, including a reduction of water withdrawals from the main well field due to a possible future decrease in water availability. Based on KPIs, sustainable long-term strategies are evaluated in order to identify the most suitable solution for dynamic sustainable management of the water supply system.

Health and Drinking Water Supply Vulnerabilities to Climate Variability in Coastal and Drought-Prone Areas of Bangladesh

The objectives of the study are to understand the relationship among climate variability, waterborne disease, and the drinking water supply vulnerabilities in coastal and drought-prone areas of Bangladesh. The study used both qualitative and quantitative approaches. Qualitative data were collected by conducting stakeholder interviews and focus group discussion. Quantitative data were collected using survey and from hospital records. The study was conducted in three sites, one in a drought-prone area and two in coastal areas. Correlation analysis provided the relationship among climate variables, health outcomes, and water supply system. The regression analysis was used to determine the health vulnerabilities of the communities with time. Temperature, rainfall, humidity, and hot and cold days per year adversely affected the groundwater table and functionality of water technologies in both coastal and drought-prone sites, which in turn affects the accessibility and quality of water and health. Diarrhea, dysentery, and stomachaches and skin diseases were found in all sites more than the usual number, whereas, jaundice and typhoid are distinct in drought-prone areas only. Strong correlations of these health outcomes with different climatic and water supply variables were observed with different magnitude. Regression analysis forecasts annual increases of 5% diarrhea, 3% stomachache, 5% skin diseases cases in coastal sites and 5% diarrhea, 3% skin disease, 3% stomachache, and 2% jaundice cases in drought-prone sites annually over the next decade. The level of significance of linear association was found to be high only for diarrheal cases. Communities are becoming more vulnerable due to climate-change-related increases in waterborne diseases and impacts on water supply. Interventions are recommended to increase the resilience of water supply systems and to reduce vulnerabilities.

A modeling framework for evaluating the drought resilience of a surface water supply system under non-stationarity

The future resilience of water supply systems is unprecedentedly challenged by non-stationary processes, such as fast population growth and a changing climate. A thorough understanding of how these non-stationarities impact water supply resilience is vital to support sustainable decision making, particularly for large cities in arid and/or semi-arid regions. In this study, a novel modeling framework, which integrates hydrological processes and water management, was established over a representative water limited metropolitan area to evaluate the impacts of water availability and water demand on reservoir storage and water supply reliability. In this framework, climate change induced drought events were selected from statistically downscaled Coupled Model Intercomparison Project Phase 5 outputs under the Representative Concentration Pathway 8.5 scenario, while future water demand was estimated by the product of projected future population and per capita water use. Compared with the first half of the 21st century (2000–2049), reservoir storage and water supply reliability during the second half century (2050–2099) are projected to reduce by 16.1% and 14.2%, respectively. While both future multi-year droughts and population growth will lower water supply resilience, the uncertainty associated with future climate projection is larger than that associated with urbanization. To reduce the drought risks, a combination of mitigation strategies (e.g., additional conservation, integrating new water sources, and water use redistribution) was found to be the most efficient approach and can significantly improve water supply reliability by as much as 15.9%.

Optimal fresh water blending: A methodological approach to improve the resilience of water supply systems

Climate change and socioeconomic factors have increased the complexity of urban water supply systems. Thus, fresh water sources are being gradually diversified to improve the reliability and resilience of the systems. However, as the number of source blending options grows, optimization tools are needed to design drinking water supply systems that comply with indicators of cost, resilience, and water quality. This paper proposes a pioneering methodological approach, based on an ant-colony-optimization (ACO) algorithm, to optimize the blending of drinking water from different sources to minimize operational costs of a given system originating from a number of impaired water sources while complying with water quality standards. To evidence the potential of the ACO algorithm to solve such a system, a virtual case study was designed that considers eight fresh water sources, including seawater desalination and potable reuse. Seven scenarios were developed with different weightings to service outage, water conveyance and treatment costs while complying with water quality goals in regard to total organic carbon, nitrates, and total dissolved solids. It was shown that the cost per volumetric unit of water can vary considerably depending on the weightings of the three cost items. This paper provides a rigorous scientific approach to propose a methodology supporting the decision-making process of selecting a mixture of different sources to achieve the overall lowest system cost. Hence, this work contributes to improving the resilience and sustainability of urban water supplies.

Integrated water resources system dynamics modeling and indicators for sustainable rural community

The water resources management may face serious challenges under climate change. In order to efficiently utilize water resources and reduce loadings on centralized water supply systems, it is necessary for each water user to reduce their water requirements. Rural community consumes the great portion of water resources in Taiwan due to high irrigation water demands and thus is concerned in this study. The rural community considers having both external domestic water supply and irrigation systems, and installing reuse system and constructed wetland to provide harvested rainwater and reclaimed water. The purpose of this study is to establish an integrated water resources system dynamics model and propose indicators for quantitatively evaluating the water supply system of a rural community. The three indicators are designed to evaluate water saving efficiency, tolerance of drought duration, and influence of insufficient irrigation water on crop yields. The results show that the combination of the constructed wetland and reuse system possesses more eminent stability than the reuse system alone. The integrated water resources system may reduce up to 32 % of domestic water demands and 7.8 % of irrigation water demands from external systems, respectively. At the same time, the domestic system owns higher resilience. In conclusion, the results indicate that the reuse system and constructed wetland can significantly improve the stability and resilience of water supply system. The study on integrated water resources system for rural community desires more researches. Besides, the influence of climate change and water quality of reclaimed water should be further considered.

Testing the resilience of water supply systems to long droughts

Public water supply systems are designed to maintain water supply through extended periods of dry weather without excessive cost or environmental damage. During a drought, water suppliers can take further measures to enhance supplies or reduce demand. The introduction of drought measures is usually formalised in a drought plan, but there is often little evidence that the plan will prove successful during a range of feasible droughts. As the climate changes, recent hydrological data may be a poor guide to future drought, and planned actions may prove insufficient to maintain adequate water supplies. This paper describes a method for testing the resilience of water company drought plans to droughts that are outside recent hydrological experience. Long severe droughts of the nineteenth century provide an opportunity to test water supply system behaviour in a range of realistic droughts. The method developed combines system modelling with an interactive approach that asks water system managers to work through the actions that they would take at different stages of the drought, without knowledge of subsequent drought development. The approach was tested for two contrasting English water resource systems. In both cases, the existing water supply and drought planning measures succeeded in maintaining water supply, but significant demand restrictions and engineering measures had to be introduced. Wider use of the method by water supply planners should allow the refinement of drought and water supply plans, and will also create increased awareness of the actions necessary to manage a range of droughts.