The book provides a scientific approach into appraising Intermittent Water Supply (IWS) on a global scale through the analysis of available information and data based on a structured methodology for estimating the population affected by IWS worldwide both by country and by geographical regions. The root causes and the implications of IWS are dealt with in a concise manner providing a detailed account of the reasons for resistance to change towards 24x7 supply. A major contribution of the book is in providing an understanding of water losses in the context of IWS as well as the related difficulties in leakage detection and metering under such conditions. A methodology is presented for transitioning from IWS to continuous supply covering technical, social and communication issues which are considered of paramount importance for a successful transition. Relevant case studies from across the globe are included in the book to provide evidence based information and data relating to the many and diverse challenges faced daily by water utilities operating their networks under IWS.

Safe drinking water is paramount for the health and wellbeing of all human populations. Water is extracted from surface and groundwater sources and treated to comply with drinking water standards. The water is then circulated through the drinking water distribution system (DWDS). Within the DWDS, water quality can deteriorate due to microbiological growth, chemical reactions, interactions with ageing and deteriorating infrastructure, and through maintenance and repair activities. Some DWDS actions may serve to improve water quality; however, these can adversely impact the drinking water system and cause instances of poor water quality or disease outbreaks. We invited papers covering examinations of DWDS design and operational practices and their impact on water quality. We received papers based on practical research in real DWDS and laboratory test facilities. We also received papers on novel modelling approaches. A wide range of water quality aspects was gathered, including temperature, disinfection, bacterial communities and biofilm, (fecal) contamination and QMRA, and the effects of flushing and intermittent supply.

Water utilities worldwide lose 128 billion cubic meters annually, causing annual monetary losses estimated at USD 40 billion. Most of these losses occur in developing countries (74%). This calls for rethinking the challenges facing water utilities in developing countries, foremost of which is the assessment of water losses in intermittent supply networks. Water loss assessment methods were originally developed in continuous supply systems, and their application in intermittently operated networks (in developing countries) is hindered by the widespread use of household water tanks and unauthorised consumption. This study provides an extensive review of existing methods and (software) tools for water loss assessment. In addition, several new methods were developed, which offer improved water loss assessment in intermittent supply. As the volume of water loss varies monthly and annually according to the amount of supplied water, this study proposes procedures to normalise the volume of water loss in order to enable water utilities to monitor and benchmark their performance on water loss management. The study also developed a novel method of estimating apparent losses using routine data of WWTP inflows, enabling future real-time monitoring of losses in networks. Different methods have also been suggested to estimate the unauthorised consumption in networks. This study found that minimum night flow analysis can still be applied in intermittent supply if an area of the network is supplied for several days. Furthermore, this study concluded that water meter performance is enhanced in intermittent supply conditions. However, continuous supply in the presence of float-valves significantly reduces the accuracy of water meters. Finally, this study provides guidance and highlights several knowledge gaps in order to improve the accuracy of water loss assessment in intermittent supply. Accurate assessment of water loss is a prerequisite for reliable leakage modelling and minimisation as well as planning for, and monitoring of water loss management in distribution networks.

The Special Issue on Advances in Water Distribution Networks (WDNs) explores four important topics of research in the framework of WDNs, namely simulation and optimization modelling, topology and partitioning, water quality, and service effectiveness. With regard to the first topic, the following aspects are addressed: pressure-driven formulations, algorithms for the optimal location of control valves to minimize leakage, the benefits of water discharge prediction for the remote real time control of valves, and transients generated by pumps operating as turbines. In the context of the second topic, a topological taxonomy of WDNs is presented, and partitioning methods for the creation of district metered areas are compared. In relation to the third topic, the vulnerability to trihalomethane is assessed, and a statistical optimization model to minimize heavy metal releases is presented. Finally, the fourth topic focusses on the estimation of non-revenue water, including leakage and unauthorized consumption, and on the assessment of service under intermittent supply conditions.

This book highlights the likely impacts of climate change in terms of global and national water securities, how different countries are attempting to address these complex problems and to what extent they are likely to succeed. A major global concern at present, especially after the social and economic havoc that has been caused by COVID-19 in only one year, is how we can return to earlier levels of economic development patterns and then further improve the process so that sustainable development goals are reached to the extent possible by 2030, in both developed and developing countries. Mankind is now facing two existential problems over the next several decades. These are climate change and whether the world will have access to enough water to meet all its food, energy, environment and health needs. Much of expected climate change impacts can be seen through the lens of extreme hydrological events, like droughts, floods and other extreme hydrometeorological events. Chapter 7 is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.Chapter 12 is available open access under a Creative Commons Attribution-NonCommercial 4.0 International License via link.springer.com.

Urban water security is crucial for achieving sustainable development, peace, and human health and well-being. Framing urban water security is challenging due to the complexity and uncertainty of its definition and assessment framework. Several studies have assessed water security in widely divergent ways by granting priority indicators equal weight without considering or adapting to local conditions. This dissertation develops a new urban water security definition and assessment framework applicable to water scarce cities, with a focus on Madaba, Jordan. It takes a novel and systematic approach to assessing urban water security and culminates in integrated urban water security index (IUWSI) as a diagnostic tool and guide management actions. The dissertation suggests a new working definition of urban water security based on the United Nations (UN) Sustainable Development Goal 6.1 on safe drinking water for all and the human rights on water and sanitation as follows: The dynamic capacity of water systems and stakeholders to safeguard sustainable and equitable access to water of adequate quantity and acceptable quality that is continuously, physically and legally available at an affordable cost for sustaining livelihoods, human well-being and socioeconomic development, ensuring protection against waterborne pollution and water-related disasters, and for preserving ecosystems in a climate of peace and political stability. This proposed definition captures issues at the urban level of technical, environmental and socioeconomic indicators that emphasize credibility, legitimacy and salience. The assessment framework establishes a criteria hierarchy, consisting of four main dimensions to achieve urban water security: drinking water and human well-being, ecosystem, climate change and water-related hazards and socioeconomic aspects (together, DECS). The framework enables the analysis of relationships and trade-offs between urbanization, water security and DECS indicators. The dissertation also provides a structured analysis to understand how urban water is managed in intermittent water supply system, by conducting a water balance analysis after quantifying the components of water losses in Madaba’s water distribution network. The findings showed that Madaba's non-revenue water (NRW) amounted to annual loss of about 3.5 million m3, corresponding to financial losses of 2.8 million USD to the utility, of which 1.7 million USD is the cost of real losses. The dissertation provided an intervention strategy for strengthening infrastructure resilience and reducing leakage via the infrastructure, repair, economic, awareness and pressure (IREAP) framework. The IREAP framework provides a robust strategy to shift intermittent water supply (IWS) into continuous water supply. The IUWSI highlighted the state of water security in Madaba, Jordan and identified the means of implementation to move towards achieving urban water security based on the priorities for Madaba. The drinking water and human wellbeing dimension was the most important priority, receiving a weight of 66.22%, followed by ecosystem (17.15%), socioeconomic aspects (10.18%), and climate change and water-related hazards (6.45%) dimensions. The IUWSI indicated that the urban water security in Madaba is reasonable with a score of 2.5/5 and can meet the minimum requirements in several dimensions, but nonetheless, it has many loopholes to cover. Gaps are clear in the climate change and water-related hazards, and socioeconomic dimensions with scores of 1.6/5 and 2.237/5 respectively. Additionally, specific shortcomings are found in indicators such as water availability, reliability, diversity, and public health. The IUWSI framework assists with a rational and evidence-based decision-making process, which is important for enhancing water resource management in water-scarce cities