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To achieve a successful and sustainable adaptation to climate change we need to transform the way we think about change. Much water management research has focused on technical innovation with a range of new solutions developed to achieve a ‘more sustainable and integrated urban water management cycle’. But Danish municipalities and utility companies are struggling to bring suchsolutions into practice. ‘Green infrastructure’, for example, requires the consideration of a larger range of aspects related to the urban context than the traditional urban water system optimization. There is the need for standardized methods and guidelines to organize transdisciplinary processes where different types of knowledge and perspectives are taken into account. On the basis of themacro–meso–micro pattern inspired by complexity science and transition theory, we developed a conceptual framework to organize processes addressing the complexity characterizing urban water management in the context of climate change. In this paper the framework is used to organize a research process aiming at understanding and unfolding urban dynamics for sustainable transition. The final goal is to enable local authorities and utilities to create the basis for managing and catalysing the technical and organizational innovation necessary for a sustainable transition towards climate change adaptation in urban areas. To achieve a successful and sustainable adaptation to climate change we need to transform the way we think about change. Much water management research has focused on technical innovation with a range of new solutions developed to achieve a “more sustainable and integrated urban water management cycle”. But, Danish municipalities and utility companies are struggling to bring such solutions into practice. “Green infrastructure”, for example, requires the consideration of a larger range of aspects related to the urban context than the traditional urban water system optimization. There is the need of standardized methods and guidelines to organize transdisciplinary processes where different types of knowledge and perspectives are taken into account. On the base of the macro-meso-micro pattern inspired by complexity science and transition theory, we developed a conceptual framework to organize processes addressing the complexity characterizing urban water management in the context of climate change. In this paper the framework is used to organize a research processes aiming at understanding and unfolding urban dynamics for sustainable transition. The final goal is to enable local authorities and utilities to create the basis for managing and catalyzing the technical and organizational innovation necessary for a sustainable transition towards climate change adaptation in urban areas.

The Water supply and sanitation Technology Platform (WssTP) was initiated by the European Commission in 2004. It is led by industries in collaboration with academics, research organisations and water users to help structure the European Research Area and identify R&D needs for the water sector. In December 2008, the board of the WssTP identified the need to create a Task Force on Climate Change in order to build a working group focused on the issue and able to assist the EU Commission in the related Calls for Projects. The Task Force on Climate Change did a review on the research and technology development (RTD) needs related to each of the WssTP topics, highlighting the challenges they will face in a climate change context. This paper is based on the review carried out and presents its main conclusions. The RTD topics identified involve a broad range of expertise areas and can be divided into two main groups: mitigation and adaptation. The latter will be brought to the fore in this paper.

India is facing major challenges in its water resources management (WRM) sector. Water shortages are attributed to issues such as an explosion in population, rapid urbanization and industrialization, environmental degradation and inefficient water use, all aggravated by changing climate and its impacts on demand, supply and water quality. This paper focuses on the contemporary and future situation in the Cauvery river basin in Southern India, shared by different states, predominantly Karnataka and Tamil Nadu. As water issues largely fall under the authority of the states, inter-state water disputes have a long tradition in the Cauvery river basin. Future changes in precipitation during the two monsoon seasons will only increase these tensions. Both states depend on the arrival of these monsoon rains to water their crops and to replenish the groundwater. The paper identifies the major challenges and general possible solutions for sustainable WRM within the river basin. It synthesises the relevant literature, describes practices that should be addressed in the scope of integrated WRM – including water availability increase and demand management – and stresses the need for further quantitative analyses.

In many locations, climate change may significantly reduce urban water supplies and could also affect water demand. With uncertainty around future climate, supply-demand planning needs to adapt. This paper addresses the question: How does climate change alter Integrated Resource Planning (IRP) for urban water? The paper covers the setting of planning objectives in the face of climate change, assessing the impacts of climate change on urban water supply and water demand, and considers the available responses. While climate change represents a major challenge for urban water planning it also reinforces key principles of IRP such as adaptive management, the central role of water conservation and need for public engagement in water planning.

Adaptation of water resources to climate change, drought management strategies, and hydrological and reservoir modelling have become serious issues in the context of climate change uncertainty. The aim of this paper is to introduce methods and tools for hydrological analysis and robust reservoir performance evaluation in this time of deep uncertainty. Newly developed lumped water balance and reservoir simulation models will be used to perform hydrological analysis, and a robust reservoir storage capacity reliability assessment will also be conducted. The hydrological data in relation to climate change will be constructed using two climatological datasets created by statistical downscaling tools LARS WG and ENSEMBLE Downscaling Portal. The hydrological analysis and the temporal reliability of the assessment of reservoir storage capacity and robustness in the context of climate change uncertainty will be presented as a case study of the Vir I reservoir and the Svratka River basin in the Czech Republic, in central Europe. The resulting models show a decrease in long-term mean flow, ranging from 6% to 32%, and in reservoir outflow from 1.5% to 26%, depending on the timescale, downscaling tools and emission scenarios.

The aim of the paper is to present climate chance impact on drinking water supply and assess availability of current water resources to meet the increasing demands in climate change conditions for the city of Skopje. Series of monthly precipitation and temperature data are generated up to 2050, using recorded data and data for predicted changes of air temperature and precipitation according to climate change scenarios developed for the Republic of Macedonia within the Third National Communication. Climate change impact on drinking water supply is assessed using statistical models for dependence of the water supply data to the main climate parameters: temperature and precipitation. Forecast of future water quantities includes implementation of multi regression models defined with a set of independent variables: number of population for time sets (t, t − 1, t − 2, t − 3), precipitation and air temperature including predicted changes of the data under climate change conditions for the same time sets. Two scenarios are analysed: first – predicts the number of population until 2050 remains nearly the same as nowadays, second – predicts increase of number of population on average annual rate of increase of 0,58%. Results are indicating shortage of available water resources for population and industry in climate change scenarios (increasing of temperatures and decreasing of precipitations) and increase of population. Understanding the vulnerability of both water resources and variability of drinking water demands for the city of Skopje results in identifying the most dominant factors that influence vulnerability. It is vital to ensuring sustainable water management in the region.

Water supply systems that operate intermittently rather than continuously are highly complex. This arises from the interaction of large numbers of internal and external factors that produce major consequences for system operation and management. Handling these problems requires understanding, and to some extent eliminating, their causes. In this paper, Lusaka Water and Sewerage Company, Zambia, is used as a case study that shows how poor governance, demographic and economic dynamics, hydrologic regime change, poor system management and operation, unplanned system extensions, limited skilled manpower, poor electricity supply and lack of customer awareness all contribute to sustaining intermittent water supply. Interdisciplinary approaches are recommended to explore interplays between governance, climate change and technical factors when developing solutions to intermittent supplies.

This paper presents an integrated, computer-based generic framework to couple urban water related models into a decision support tool (DST) for urban-water management. The DST, built on a participatory modelling approach, enables stakeholders to analyze impacts of climate variation, population growth, and alternative management solutions ranging from centralized to distributed options. The coupling of external models, building of the DST, and execution of simulation processes is achieved by employing GoldSim, which is linked to a database management tool and a shared library. A post-processing package generates outcomes for decision makers in the form of a new criterion, the Water System Performance Index (WSPI). The application of DST is demonstrated for the water service area of the Salt Lake City Department of Public Utilities (SLCDPU). Results show that a decentralized alternative increases the reliability of the system without changing the system's vulnerability. Centralized alternative improves the overall performance of the system based on WSPI results, but decrease in performance is still noticeable under the hot and dry climate condition. Overall, the system is very sensitive to changes in climatic conditions. Results show that during droughts, supply management is not the sole solution and compulsory demand-management practices should be instigated.

Sustaining the water supply in megacities is an enormous challenge. To address this challenge, it is especially important to predict water demand changes in megacities. This paper presents a system dynamics model to predict the future water demands of different sectors considering multiple factors, including population, structure of the economy, and water supply and use technologies. Compared with traditional methods such as the time series method and structure analysis method, the proposed model takes into account the interconnections, non-linear relationships and feedbacks between the various factors in a systems context. The model is applied to Beijing, a megacity with a population over 20 million and very limited water availability. It is found that the total water demand is likely to increase by at least 36.1% (up to 62.5%) by 2030 compared with that in 2011, and the water deficits vary from −0.36 × 109 to 1.80 × 109m3 in 2030. In addition, scenarios are designed to account for impacts associated with economic development, climate change and inter-basin water transfers. It is shown that climate change may have a large impact on the water supply reliability in Beijing. The water shortage problems can be alleviated via inter-basin water transfers.

Rapid urbanisation, population growth and the effects of climate change drive the need for sustainable urban water management (SUWM) in Asian cities. The complexity of this challenge calls for the integration of knowledge from different disciplines and collaborative approaches. This paper identifies key issues and sets the stage for interdisciplinary research on SUWM in Asia. It reports on the initial stages of a SUWM research programme being undertaken at Monash University, Australia, and proposes a framework to guide the process of interdisciplinary research in urban water management. Three key themes are identified: (1) Technology and Innovation, (2) Urban Planning and Design, and (3) Governance and Society. Within these themes 12 research projects are being undertaken across Indonesia, China, India and Bangladesh. This outward-looking, interdisciplinary approach guides our research in an effort to transgress single-discipline solutions and contribute on-ground impact to SUWM practices in Asia.

Climate change is likely to cause higher temperatures and alterations in precipitation patterns, with potential impacts on water resources. One important issue in this respect is inflow to drinking water reservoirs. Moreover, deteriorating infrastructures cause leakage in water distribution systems and urbanization augments water demand in cities. In this paper, a framework for assessing the combined impacts of multiple trends on water availability is proposed. The approach is focused on treating uncertainty in local climate projections in order to be of practical use to water suppliers and decision makers. An index for water availability (WAI) is introduced to quantify impacts of climate change, population growth, and ageing infrastructure, as well as the effects of implementing counteractive measures, and has been applied to the city of Bergen, Norway. Results of the study emphasize the importance of considering a range of climate scenarios due to the wide spread in global projections. For the specific case of Bergen, substantial alterations in the hydrological cycle were projected, leading to stronger seasonal variations and a more unpredictable water availability. By sensitivity analysis of the WAI, it was demonstrated how two adaptive measures, increased storage capacity and leakage reduction, can help counteract the impacts of climate change. © 2019 The Authors. Published by IWA Publishing. This work is licensed under a Creative Commons Attribution 4.0 International License.

This paper presents an assessment framework that analyses the impacts of climate change on the water diversion strategies of a water transfer project in China. A water diversion strategy consists of high and low water levels as well as related diversion flows in four operating periods: pre-flood, flood, post-flood and non-flood periods. The optimal water diversion problem is defined as a multi-objective problem with two conflicting objectives: minimising human and ecological water supply shortages, and solved by the popular non-dominated sorting genetic algorithm II (NSGA-II). The derived Pareto-optimal solutions are then evaluated using the predicted runoffs based on an ensemble of three general circulation models under three climate scenarios. Results obtained from the study catchment show that intra-annual distribution of future runoff changes. The optimal solutions on the Pareto front have greatly varying performance under a climate scenario. It is critical to reveal the different impacts of climate change on the water shortages over the four operating periods, in particular when an increase of water shortage in one period is masked by a reduction in one or more periods. This study illustrates that the framework can be used to identify resilient water diversion strategies to mitigate the potential impacts of climate change on the operation of a water transfer project.

This paper aims to propose a decision support system (DSS) for evaluating the climate change impacts on water supply–demand and inundation; and assessing the risks for water shortage and inundation under future scenarios. The proposed DSS framework is universal and flexible, which comprises five modules integrated by a geographic information system platform, including the modules of (1) scenario rainfall and temperature projection under climate change, (2) impact assessment of water supply–demand, (3) impact assessment of inundation, (4) assessment of vulnerability and risk, and (5) adaptation strategy. A case study in southern Taiwan was performed to demonstrate how the DSS provides information on the climate change impacts and risks under future scenarios. The information is beneficial to the authorities of water resources management for understanding the spatial risks for water shortage and inundation, and planning suitable adaptation strategies for the locations with larger risks.

In this paper the integration of water resources management with regard to reservoir management in an eco-hydrological model is described. The model was designed to simulate different reservoir management options, such as optimized hydropower production, irrigation intake from the reservoir or optimized provisioning downstream. The integrated model can be used to investigate the impacts of climate variability/change on discharge or to study possible adaptation strategies in terms of reservoir management. The study area, the Upper Niger Basin located in the West African Sahel, is characterized by a monsoon-type climate. Rainfall and discharge regime are subject to strong seasonality. Measured data from a reservoir are used to show that the reservoir model and the integrated management options can be used to simulate the regulation of this reservoir. The inflow into the reservoir and the discharge downstream of the reservoir are quite distinctive, which points out the importance of the inclusion of water resources management.

The yearly water main failure frequency is a central performance indicator to describe the structural quality of a water distribution network. Besides age related deterioration, events such as severe climatic conditions or intensified third party construction may cause sudden seasonal increases in failure frequency trends. For the cold regions of Canada and the dry regions of Australia, several studies exist describing the impacts of climatic failure frequencies on water main failure variations. Failure prediction modelling applied to Austrian supply systems have shown that irregularities in overall failure trends were not explainable with commonly used model covariates like material, vintage, diameter or the number of previous breaks. Analysing the monthly failure frequencies of several Austrian utilities, seasonal differences and variations in failure frequencies are recognizable. The research described in this paper therefore focused on analysing if climatic impacts are responsible for these variations. In a first step, climatic indicators, which are able to describe seasonal climatic variations in moderate climate regions, were derived. In a next step the correlation between summer and winter failure frequencies to these climatic indicators was analysed. The indicators taken into account were, e.g. the decisive freezing index (DFI), the summer rain deficit (RDs) or the amount of successive hot days (AHD). The research has shown that in all investigated climatic zones of Austria, the severity of the winter season influences failure frequencies. A dependency between winter failure frequency and the DFI was significant especially for rigid material types and for diameters up to 200 mm. So far, soil moisture effects have only shown a slight significance. Nevertheless, the indicator AHD has shown a correlation to failure frequencies in the dryer climate zones of Austria. This is of further interest as it is very likely that the AHD is going to increase due to climate change.

South Africa's water resources are unequally distributed over space and time and an already stressed water resource situation will only be exacerbated by climate change if current predictions are correct. The potential for conflict over increasingly strained water resources in South Africa is thus very real. In order to deal with these complex problems, national legislation is demanding that water resource management be decentralized to the local level where active participation can take place in an integrated manner in accordance with the principles of Integrated Water Resource Management (IWRM). However, administrative and political boundaries rarely match those of catchments as, throughout South Africa, rivers have been employed extensively to delineate administrative and political boundaries at a number of spatial scales. The aim of this research is to determine if rivers act as dividing or uniting features in a socio-political landscape and whether topography will influence their role in this context. The Orange-Senqu River is used as a case study. This paper goes on to consider the implications of this for catchment management in South Africa. No study known to the authors has explored the effect of the river itself, and its topographic setting, on the drivers that foster either conflict or cooperation, and allow for participatory management. This study presents evidence that the topography of a catchment has the ability to aggravate or reduce the impact of the variables considered by water managers and thereby influence the role of a river as a dividing or uniting feature. South Africa's proposed form of decentralized water management will have to contend with the effects of different topographies on the way in which rivers are perceived and utilized.

The Star City rainwater harvesting system (RWHS) was featured in the December, 2008, issue of Water 21. The article highlighted that the RWHS has a 3,000 m3 rainwater tank used in water saving, flood mitigation, and emergency response. Since then, many news media, public officials, and people from both South Korea and abroad have visited the RWHS. In this paper, two years of the system's operational data are presented and its role in short- and long-term climate change adaptation is investigated. The downstream sewer system has become safe for a 50-year rainfall without upgrading the existing sewer system, which was designed for a 10-year period. The 26,000 m3 of water saved has reduced the energy requirement of transferring water from a distant area. The success of the Star City RWHS has influenced 47 cities across South Korea, including Seoul, to enact regulations on rainwater management. It has shown that decentralized rainwater management can supplement the existing centralized system to ensure its safety.

This paper assesses the impacts of climate change on water resources in the Western Macedonia water district, located in northern Greece. Some critical water management issues, such as reservoir storage and water supply for agriculture and domestic use, are investigated. A conceptual water balance model was calibrated using monthly historical hydrometeorological data. The proposed model was applied in the entrance of the Polyfyto reservoir in order to estimate runoff values under a transient scenario (UKTR) referring to years 2032 and 2080. The results show that the mean annual runoff, mean winter runoff and summer runoff values, annual maximum and minimum values, as well as monthly maximum and minimum, would be reduced. By using this transient scenario, the risk associated with the water supply for power production, agriculture and domestic use has been evaluated under conditions of altered runoff. Increases of the risks associated with the annual quantities of water supply have been observed.

Drought and concern over climate change has led to the increased use of distributed water systems in Australia to supplement centralised supply systems. A literature review carried out by the Institute for Sustainable Futures (ISF) into the energy consumption of water infrastructure found that very little data on energy consumption exists, particularly for distributed systems. This paper reviews the findings of the literature review and presents results from a preliminary monitoring study on the energy implications of household rainwater systems. Typical household systems that are currently being installed in ouses cross Australia use approximately 1.5 kWh/kL. © IWA Publishing 2010.

People always have had to confront themselves with the unforeseeable behaviour of the environment and climatic variability. However, for the first time in the history of our planet, climatic change is today caused by human activity. This situation of global crisis is caused by a series of factors that make of the present emergency a new scenario, exposing entire areas of the planet to the risk of lack of water and desertification. However, desert and desertification are two different things. The desert is characterised by a precise ecological balance established in the course of time by specific climatic conditions. These precise conditions have generated knowledge capable of facing adversities with appropriate techniques for capturing and distributing water, for preserving soil, for recycling and for the economical use of energy. The paper analyse the different solutions adopted in ancient periods in order to cope with water scarcity. In particular the study compares the Neolithic experiences in the Puglia Region and in the Sassi di Matera (Italy) with similar structures in the rest of Mediterranean. These traditional solutions are today proposed in a new innovative form to cope with environmental crises.

With the growth of urban areas and climate change, decisions need to be taken to improve water management. This paper reports an assessment of the impact of greywater recycling systems on catchment scale hydrological flows. A simulation model developed in InfoWorks CS (Wallingford Software Ltd) was used to evaluate how river flows, sewer flows, surface runoff and flooding events may be influenced when grey water recycling systems of different number and scale are implemented in a representative catchment. The simulations show the effectiveness of greywater recycling systems in reducing total wastewater volume and flood volume. However, no hydraulic impacts due to implementation of greywater was identified by the model.

During the last century, much of the United States experienced warming temperatures and changes in amount and intensity of precipitation. Changes in future climate conditions present additional risk to water and watershed managers. The most recent release of U.S. EPA's BASINS watershed modeling system includes a Climate Assessment Tool (CAT) that provides new capabilities for assessing impacts of climate change on water resources. The BASINS CAT provides users with the ability to modify historical climate and conduct systematic sensitivity analyses of specific hydrologic and water quality endpoints to changes in climate using the BASINS models (Hydrologic Simulation Program – FORTRAN (HSPF)). These capabilities are well suited for addressing questions about the potential impacts of climate change on key hydrologic and water quality goals using the watershed scale at which most important planning decisions are made. This paper discusses the concepts that motivated the CAT development effort; the resulting capabilities incorporated into BASINS CAT; and the opportunities that result from integrating climate assessment capabilities into a comprehensive watershed water quality modeling system.

Urbanization, land subsidence and sea level rise will increase vulnerability to droughts in the urbanized low-lying areas in the western part of the Netherlands. In this paper a possibility is explored to decrease vulnerability of urban areas by implementing an alternative water supply option. A four component vulnerability framework is presented that includes threshold capacity, coping capacity, recovery capacity and adaptive capacity. By using the vulnerability framework it is elaborated that current water supply strategies in the Netherlands mainly focus on increasing threshold capacity by constructing improved water storage and delivery infrastructure. A complete vulnerability decreasing strategy requires measures that include all four components. Adaptive capacity can be developed by starting experiments with new modes of water supply. A concept which is symbolically called ‘the closed city’ uses local urban rainfall as the only source of water supply. The ‘closed city’ can decrease the water dependence of urban areas on (1) the surrounding rural areas that are diminishing in size and that are increasingly under strain and (2) river water resources that will probably be less constant and reliable as a result of climate change.

Climate change raises many concerns for urban water management because of the effects on all aspects of the hydrological cycle. Urban water infrastructure has traditionally been designed using historical observations and assuming stationary climatic conditions. The capability of this infrastructure, whether for storm-water drainage, or water supply, may be over- or under-designed for future climatic conditions. In particular, changes in the frequency and intensity of extreme rainfall events will have the most acute effect on storm-water drainage systems. Therefore, it is necessary to take future climatic conditions into consideration in engineering designs in order to enhance water infrastructure investment planning practices in a long time horizon. This paper provides the initial results of a study that is examining ways to enhance urban infrastructure investment planning practices against changes in hydrologic regimes for a changing climate. Design storms and intensity–duration–frequency curves that are used in the engineering design of storm-water drainage systems are developed under future climatic conditions by empirically adjusting the general circulation model output, and using the Gumbel distribution and the Chicago method. Simulations are then performed on an existing storm-water drainage system from NE Calgary to investigate the resiliency of the system under climate change.

Previous studies have sought to develop econometric models of water supply systems, which can be used to predict future water supply costs; none, however, have investigated the influence of climatic factors. In this paper, climatic and other regional influences on the costs of water supply in the USA are explored using multivariate analysis of water supply costs from water supply utilities located throughout the USA. Results showed that over 90% of the variation in present water supply capital and operating costs for surface and ground water systems can be explained by variations in quantity of water delivered, with other variables, particularly regional climate, playing a negligible role. An analysis of the historic development of water supply in the USA showed that capital expenses for water supply systems are a relatively small component of the present total annual costs because: (1) the original capital expenditures were reduced for utilities due to large public subsidization; (2) repayment of capital expenditures is now complete owing to the long time period since the original investments; and (3) new policies encourage demand management instead of supply expansion. Therefore, the present costs of water supply are not related to climate and thus are not a useful guide to future costs in studies that evaluate climate change impacts.

This paper describes a probability-based method for assessing the potential impact of climate change on urban water supply systems. Specifically, the assessment method uses probability distributions to place a confidence level on the plausible values of response variables. The Benalla water supply system has been used to demonstrate applicability of the proposed assessment method. For the application, the impact of the 2030 climate change scenarios on streamflows and system yield has been examined. The preliminary results have demonstrated that the proposed assessment method can provide valuable insights into the impact of climate change on water supply systems, allowing it to be incorporated into planning decisions.

This paper examines factors affecting water availability and hydrological trends of water supply. The relative impacts of the different factors have been assessed on a planning time frame of around 30 years. It is demonstrated that the non-greenhouse processes of multi-decadal climate change and el Niño-la Niña climate change will almost certainly be more significant than greenhouse induced climate change. Further, in developing countries, increased water consumption, population growth, and urbanization are likely to be the dominant factors when considering water availability. The type of responses that a water supply organization can make are discussed.

This paper presents the first basin-wide assessment of the potential impact of climate change on the hydrology and production of the Ganges system, undertaken as part of the World Bank’s Ganges Strategic Basin Assessment. A series of modeling efforts, downscaling of climate projections, water balance calculations, hydrological simulation and economic optimization, inform the assessment. The authors find that projections of precipitation across the basin, obtained from 16 Intergovernmental Panel on Climate Change-recognized General Circulation Models are highly variable, and lead to considerable differences in predictions of mean flows in the main stem of the Ganges and its tributaries. Despite uncertainties in predicted future flows, they are not, however, outside the range of natural variability in this basin, except perhaps at the tributary or sub-catchment levels. The authors also find that the hydropower potential associated with a set of 23 large dams in Nepal remains high across climate models, largely because annual flow in the tributary rivers greatly exceeds the storage capacities of these projects even in dry scenarios. The additional storage and smoothing of flows provided by these infrastructures translates into enhanced water availability in the dry season, but the relative value of this water for the purposes of irrigation in the Gangetic plain, and for low flow augmentation to Bangladesh under climate change, is unclear.