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Cities and towns have developed stormwater systems to remove the runoff from developed areas. Although the systems are efficient in mitigating local drainage issues, they transfer pollutants and sediment to receiving waters, increase the flashiness of the flow regime and reduce ecological health. Water Sensitive Urban Design (WSUD) approaches are now being adopted to mitigate urbanisation and climate change impacts. This paper reports on the result of reviewing more than 200 papers leading to the conclusion that further investigation is vital to understand how WSUD systems can mitigate climate change impacts and rapid urban development due to the population growth and ongoing shift in populations to cities. Further, the importance of understanding the role of WSUD in increasing the liveability of urban areas. The paper also identifies both strengths and limitations of WSUD which is vital to promote realistic expectations and consequently appropriate designs, budgets, and maintenance regimes. [ABSTRACT FROM AUTHOR]

There is an urgent need for urban environments to be flood resilient due to increasing urbanization and climate change. This can be addressed by adopting sustainable drainage solutions (SuDS) in households. However, lack of knowledge and awareness among urban residents is a barrier. In this paper, we present an educational serious game called SuDSbury to overcome this barrier and a pre-/post-game survey-based evaluation to study whether the game can educate citizens (and to what degree). An exploratory study with 14 players across three game sessions suggests that playing SuDSbury induced changes in knowledge, comprehension, and personal norms regarding SuDS. However, comprehension of concepts related to urban drainage can be improved by increasing game realism. The game should be further tested with a larger sample and a diverse demographic of urban residents. The participants further found that SuDSbury is fun and engaging to play, making it suitable for broader public interventions. [ABSTRACT FROM AUTHOR]

Understanding the knowledge of climate-change impacts on water-resources is a priority. This article goes a step further with the main objective of this study to explore water-practitioners' viewpoints regarding the water supply-side and water demand-side management measures in coping with future climatic impacts to achieve urban water security. Interviews were conducted with water-professionals from regional urban water authorities of Queensland, Australia. From a water-practitioner's viewpoint, surface water is perceived to remain a high-priority water resource for the region, although climate-change is projected to make this resource more vulnerable in the area. Climate-change risks have rarely been considered as a selection-criterion when long-term water solutions were investigated by water-practitioners. Although non-pricing water demand management policies were used to reduce water demand in the region, pricing-based water demand management tools are perceived by the water-professionals to be the most effective at reducing water demand in the study area, if implemented. [ABSTRACT FROM AUTHOR]

New York City's coastlines are a mosaic of natural and man-made habitats intermixed with housing and industry, all of which are extremely vulnerable to flooding, storm surge, and damaging wave action. Risks are projected to increase over time as sea levels rise, population grows, and the frequency and severity of extreme events increase. This paper investigates the potential role of green infrastructure (GI) as a risk reduction measure, using Hurricane Sandy as a case study. Specifically, this research examines whether the type, size, and configuration of GI played a role in determining the odds of building damages. Results suggest that proximity to different GI types did affect the odds of damage, both positively and negatively, and that the impacts of both small-scale and large-scale natural features varied geographically. Results suggest that nature-based solutions to coastal flooding must be tailored to specific local conditions in order to be effective. [ABSTRACT FROM AUTHOR]

Changes in precipitation patterns associated with climate change may pose significant challenges for storm water management systems across the U.S. In particular, adapting these systems to more intense rainfall events will require significant investment, though no method currently exists for estimating the costs of these investments on a national scale. To support assessment of these costs at the national level, this paper presents a reduced-form approach for estimating changes in normalized flood depth (the volume of node flooding normalized by the area of the catchment) and the associated costs of flood prevention. This reduced form approach is calibrated to results generated by the U.S. Environmental Protection Agency's Storm Water Management Model (SWMM) for city-wide or neighborhood-level catchments in seven cities across the U.S. Estimates derived from this approach represent a reasonable approximation of storm water management adaptation costs and exhibit no systematic bias relative to results derived from SWMM. [ABSTRACT FROM AUTHOR]

Flooding can cause major disruptions in cities, and lead to significant impacts on people, the economy and on the environment. These impacts may be exacerbated by climate and socio-economic changes. Resilience thinking has become an important way for city planners and decision makers to manage flood risks. Despite different definitions of resilience, a consistent theme is that flood resilient cities are impacted less by extreme flood events. Therefore, flood risk professionals and planners need to understand flood impacts to build flood resilient cities. This paper presents a state-of-the-art literature review on flood impact assessment in urban areas, detailing their application, and their limitations. It describes both techniques for dealing with individual categories of impacts, as well as methodologies for integrating them. The paper will also identify future avenues for progress in improving the techniques. [ABSTRACT FROM AUTHOR]

Stormwater management essentially aims at controlling the surface runoff to reduce water pollution and restore ecosystem integrity. This paper reviews and discusses several optimization problems associated with this field. Different features of such problems were identified to provide a classified investigation of the literature in terms of control approach, performance criteria, stormwater management approach, and uncertainty consideration. Having evaluated the relevant literature based on these factors, the knowledge gaps were extracted. We have noticed that there is an upward trend towards sustainable management of stormwater systems to deal with climate change. Despite this progress, there are still many areas to further develop stormwater management models, many of which relate to uncertainty identification, system-level real-time control, and the proper formulation of multi-objective optimization models. Hence, integration of different criteria in optimization models, and also the study of design vs. operation of stormwater management systems are proposed as further studies. [ABSTRACT FROM AUTHOR]

Norway has frequently encountered flood damage in urban areas during recent years. In this paper the authors, taking Veumdalen catchment in Fredrikstad as an example, simulated the possible consequences in the sewer system, in the present, predicted and artificial climate scenarios. Indicators that describe (1) surface flooding, (2) surcharging sewers, (3) basement flooding and (4) combined sewer overflow (CSO) are defined to represent the adverse effects of climate change. It is concluded from the annual-based simulation that the total volume of water spilling from the flooding manholes will increase 2-4-times the increase in precipitation, and the total CSO will increase 1.5-3-times as much as the increase in precipitation. The simulation results also show that the number of flooding manholes and number of surcharging sewers may change dramatically and irregularly with a slight change of precipitation, and vary with events and durations. [ABSTRACT FROM AUTHOR]

Disaster management for urban areas is a growing priority owing to factors such as the relentless migration to cities, unplanned development, changing climate, and increasing operational and maintenance costs. New information and communication technologies offer improved opportunities to address these factors. This paper presents and describes the digital city concept as a means of capturing, analysing and applying (digital) information about the city area, its services, and their design and operation. In particular, the functionality of the digital city can be adapted for managing urban flood disasters. The paper highlights the need to manage the urban stormwater cycle integrated with urban planning. Urban flooding should be mitigated by having a judicious mix of both structural and nonstructural strategies, which are selected with the full participation of all stakeholders. The management of urban flooding is illustrated with application to the tropical island of St Maarten. [ABSTRACT FROM AUTHOR]

Frequent water stress episodes affecting urban hubs have caused a shift in urban water management towards integrated approaches and motivated a search for alternative water resources. Large-scale rainwater harvesting on the municipal scale can overcome the disadvantages of climate dependence and the volume restrictions associated with small-scale collection facilities. In this paper, two tools based on the urban metabolism concept are used to determine the water self-sufficiency potential of urban systems from urban runoff: a simple water self-sufficiency potential indicator and a socioeconomic water flow accounting scheme, which includes water losses. Both tools are applied to a densely populated coastal area that exemplifies urban centres in the Mediterranean. This approach is useful for regions with restricted data availability on water use and facilitates information dissemination to policy makers. The results indicate a significant water self-sufficiency potential for the area of study, even under projections of reduced precipitation in the area. [ABSTRACT FROM PUBLISHER]

In this paper we describe the execution of a risk-based analysis on a simple, small-scale water resources planning problem. We aim to understand whether a risk-based approach could underpin the regulated water resources planning process in England and Wales. We demonstrate the practical feasibility of the approach and identify clear benefits over the conventional planning methods. We also identify several nontrivial challenges for scaling up and caution against the view that better quality decisions would emerge naturally from risk-based analyses. Useful future research might focus on: (1) the development of practical methodologies for applying these approaches to larger, more complex resource zones; (2) identifying and overcoming problems associated with regulating a risk-based water resources planning process; and (3) developing methods of economic options appraisal that can deploy the outputs of a risk-based analysis to inform planning decisions. [ABSTRACT FROM AUTHOR]

Global flood management is a major issue for most cities which have to deal with worsening factors such as climate change and fast urban growth. Computer models have been used to model and understand urban flooding on a local scale in cities (25–50 km2). It has been practically impossible to model bigger cities in one go in sufficiently high resolution due to the heavy computations involved. The present paper describes a new modelling approach for urban flooding which allows modelling on large city scale (1000 km2) while keeping sufficient resolution, e.g. 5 m or 10 m grid. The multicell approach is applied for the city of Beijing for July 21st, 2012 flood event. Model results are compared to testimonials from the 2012 event. Comparison to traditional 2D urban flood computations shows that the multicell approach is much faster than standard detailed models while keeping a suitable level of precision. [ABSTRACT FROM AUTHOR]

Guidance on what type of rainfall to use when assessing hydraulic capacity of urban drainage systems under climate change is unclear; focus is mainly on what climate factors to use. Based on a case study in Kalmar, Sweden, this paper compares system performance using two design rainfalls, Block rainfalls and Chicago Design Storm (CDS), and selected observed rainfalls, with two methods of addressing future climate: a constant factor and Delta Change (DC) factors that depend on rainfall intensity. The use of CDS rainfalls presents the maximum hydraulic response, whereas Block rainfalls give lower responses but identify critical durations in the system, which may be useful addressing adaptation actions. Observed rainfalls of target return periods gave similar responses to CDS rainfalls, and can be applied with DC factors to address future changes in both intensity and volume. Differences between the two methods indicate a high dependence related to the maximum factors applied on the rainfalls. [ABSTRACT FROM AUTHOR]

Climate change and human activities have changed a number of characteristics of river flow in the northwest of China. Numerous problems such as water resource shortage, drying up of rivers, water pollution are the direct consequences of these changes. In this paper, we used the example of Yulin city in northwest China to assess the spatio-temporal characteristics and driving forces of annual river flow changes. Our research was based on the long-term time series of hydrological data from 1956 to 2005, to analyse annual flow in four main rivers (Kuye River, Tuwei River, Wuding River and Jialu River). The river flow depends upon the runoff characteristics of the river catchment, therefore we used variation ratio, variation index, unevenness, Runoff-Concentration Degree (RCD) and Runoff-Concentration Period (RCP) to determine the change in runoff characteristics of the four main rivers flows of the Yulin city. We tested the tendency of runoff by the Mann-Kendall non-parameter statistical method to obtain the temporal evolution law. At the same time, Kriging spatial interpolation and GIS were used to derive the spatial evolution law. The dates of climate change (precipitation) and human activities were also used to calculate the driving forces for annual runoff changes of the rivers’ catchments. Through the accumulation curves and multi-recursive techniques, we built the correlation between precipitation and runoff. The driving factors for annual runoff change were then calculated by using the runoff coefficient method. Results showed that the distribution of annual runoff was uneven and had a small accumulation in July and August, especially in Kuye River, and there seemed to be a significant reducing trend in annual runoff. Isolines and the thematic map of Mann-Kendall tests U(R) revealed that the Tuwei River's catchment is the most affected catchment, with annual runoff substantially changed. At the 5% significance level, precipitation did not significantly drop compared with annual runoff. We also found that precipitation is not the only factor responsible for the decreased annual runoff. Therefore we included human activities affect in this case study by using the past 25 years land use, water conservancy and urbanisation data. We discriminated the impacts of climate change and human activities on the surface runoff by multi-recursive analysis method and runoff coefficient method. The results showed that human activities are the direct cause for the changes of river runoff. The results of the study also revealed that the Wuding and Jialu rivers had the most and the least changes in the runoff respectively; this phenomenon should be seriously considered for future water resources planning and management. [ABSTRACT FROM PUBLISHER]

The need for efficient water resources management is currently more pressing than ever, considering population growth and increased reliability requirements, under climate change conditions. On average, one-third of the total water abstracted for urban uses is being lost due to leaks and breaks occurring in water distribution networks. This means that significant amounts of water and revenues are being lost, forcing water utilities to consider developing effective water loss and Non-Revenue Water reduction strategies. Additionally, all water utilities operating in EU countries should, by the end of 2010, develop and implement appropriate water pricing policies that will guarantee the recovery of the full cost of the water being used. This strict obligation makes the reduction of water losses an even more urgent goal that the water utilities have to achieve. The first step towards all the above-mentioned goals is to safely evaluate the performance level of the water network. Thus, the IWA Task Forces on Water Losses and Performance Indicators (PIs) developed specific tools (e.g., the standard international water balance and various PIs), to help water utilities use a common language that will assist know-how and experience exchange through an effective benchmarking process. The paper presents the results of using the above-mentioned IWA tools, in the case of the Larisa city water distribution network in Greece. This is the first time that such an attempt has taken place in Greece. During this process, the problems faced and the ways to tackle them are analyzed, focusing on the role of key factors that had to do with local conditions. Larisa's results are compared to data available from similar cases. Sensitivity analysis was used to check the impact of the variables' uncertainty to the results. Finally, water loss reduction measures are proposed towards an effective pressure management strategy and a proactive pipe maintenance policy based on safely estimating the pipes' optimum replacement time. [ABSTRACT FROM AUTHOR]

Ecosystem service (ES) assessment tools do not yet consider some of the most common urban pollutants and this study contributes to filling this gap. The methodology employed in the Modelled Estimates of Discharges for Urban Stormwater Assessments (MEDUSA) was implemented within the Land Utilisation and Capability Indicator (LUCI) to allow urban pollutant issues to be considered within a broader ES assessment context. Two land use change scenarios for the Ōtākaro/Avon River in Christchurch, New Zealand, were assessed for 2011–2020 and 2041–2050. Implementation of a limited set of blue-green infrastructure for 2011–2020 resulted in a reduction of TSS by 5–12%, of Zn by 2–5%, and of Cu by 4–7%. The simulated pollutant load values for future climate change scenarios clearly reflected the uncertainty in climate change predictions. The expanded LUCI can be employed for strategic planning of the implementation of treatment methods and types to protect waterways. [ABSTRACT FROM AUTHOR]

Climate change is raising the world's temperature, thereby causing residents to use more water for uses such as drinking and irrigation. This increase in water usage causes municipal water distribution systems (WDS) to use more electricity for pumping. In addition to the increased greenhouse gases emitted by coal-powered electricity generation, there will be a need for water system managers to increase their electricity budgets. This study uses computer modelling of fifteen different water distribution systems to quantify how much additional energy will be used in the future climate-change temperature scenarios. It was found that the average slope of the energy increase with climate-driven water demand is 0.91 with a minimum for any system of practically nothing and a maximum of 3.46. Water managers can use these values to perform budgetary planning for clime-driven future scenarios. [ABSTRACT FROM AUTHOR]

The occurrence of a representative range of pharmaceutical compounds (PhCs) in urban wastewaters was studied in two Portuguese water-scarce regions (Lisbon great area, and Faro – Algarve), involving 55 sampling campaigns during 2.5 years. The results show 16 PhCs (out of the 24 analysed) were quantified in all samples, with similar concentrations in both wastewaters. To understand to what extent seasonality affects PhC occurrence, a statistical analysis was conducted, and daily maximum air temperature was identified as a key factor, with a turning point of 20°C in Lisbon and 22°C in Faro. Some PhCs showed lower concentrations in colder (wet) months due to rainwater dilution (combined sewer systems), whereas others showed higher concentrations, reflecting an increased seasonal consumption and/or slower transformation under lower temperatures and/or shorter hydraulic retention times. Seasonal studies should therefore focus on temperature rather than on calendar seasons, increasingly uncertain due to climate change. [ABSTRACT FROM AUTHOR]

Vietnamese cities are highly vulnerable to urban flooding as a consequence of climate change and rapid urbanisation. In this study, current and future pluvial urban flood hazard was assessed for Ha Tinh city. Climate scenarios were obtained after statistical downscaling by applying a quantile-perturbation approach on ensembles of 170 global and 20 regional climate models. Flood impact analysis was based on the 1D-2D dual drainage modelling approach. Extreme daily rainfall intensities are projected to increase by 5 to 20%, whereas wet day frequency will decrease with some uncertainty. Larger changes in rainfall intensities were obtained for the finer scale climate models. Under the 95% upper limit scenario for future rainfall intensities (2071–2100), a 20-year intensity in the current climate would become a 2-year storm in the future and the flood extent is projected to increase by 30–40%. This indicates a need for climate adaptation measures and sustainable future urban planning. [ABSTRACT FROM AUTHOR]

Mounting water demand due to population growth and rapid urbanization, increasing water usage and associated water wastages make Lahore vulnerable in the context of changing climatic conditions. Lahore Development Authority (LDA), the principle planning agency in the city, introduced rainwater harvesting (RWH) system for residential buildings through clause 5.6.6 of building and zoning regulations 2014. This study explores the application of this regulation and documents associated dynamics. Findings established that a little proportion of residential buildings had constructed rooftop RWH system and yet these were not being used for its purpose. Chi-square and Cramer's V were used for understanding the factors that influenced behavior of the residents for adoption of RWH. Fittingly, the study discovered that factors that could affect peoples' willingness to adopt RWH in future were mechanism for incentives and penalties, peoples' understanding about potential benefits of RWH, and continuing regulatory requirement for RWH supported by adequate enforcement. [ABSTRACT FROM AUTHOR]

Due to the global climate change and the substantial increase in impervious area, 'never flooding' becomes an unrealistic goal. From the perspective of integrated flood management, the government and public need to reach a consensus on disasters and disaster response, and set a reasonable regional protection standard for the city to jointly respond to disasters. This study establishes an operable framework for setting protection standard. The framework uses cost-benefit analysis and data envelopment analysis to maximize the efficiency of water management, so as to compare the differences between different administrative districts under the same return period and between different return period under the same administrative districts, and then determines the best protection standard. The results find that adopting a unified protection standard will not maximize the benefits of resources, but it can be used as a basis for setting flood control standards for different public facilities and building types. [ABSTRACT FROM AUTHOR]

Rainwater tanks or cisterns are a low impact development infrastructure used to control stormwater runoff and reduce water demand. However, climate change may affect its performance due to increased rainfall intensities. This study evaluates the uncertainty on the effectiveness of cisterns to reduce peak runoff under climate change in an urban watershed in Brazil. Twelve updated intensity-duration-frequency curves, based on six Global Circulation Models and two Representative Concentration Pathways (RCP 4.5 and RCP 8.5) from the Coupled Model Inter-comparison Project 5, were used to yield hyetographs for 2 h-storm events with different recurrence intervals. Peak runoff reduction ranged between 0.4% and 5.5% for RCP 4.5 and 0.4% and 6.3% for RCP 8.5. Under climate change, a reasonable runoff control could be reached if at least 20% of the buildings installed a 5 m3 cistern. Uncertainty in future climate should be addressed in rainfall-runoff modelling to guide stormwater management decisions. [ABSTRACT FROM AUTHOR]

Climate change is projected to affect the flow regime in urban waterways adversely. This study investigates the climate change impacts on the flow regime in the Lucas Creek catchment under three Representative Concentration Pathways (RCPs): RCP 2.6, RCP 4.5 and RCP 8.5. Flow Duration Curves (FDCs) and Indicators of Hydrological Alteration (IHA) methods are used to assess flow regime variations. Results of FDCs show a maximum rise of 370% in peak flow under RCP 4.5 however, low flow increases by 40%. Monthly streamflow increases up to 380% except for October and December. Similarly, the majority of the IHA parameters also show at least a 10% increase in their magnitudes under RCP 8.5. However, some parameters such as high pulse duration and rise rate decrease by 50% under RCP 4.5. The catchment would mainly suffer severe impact variations under RCP 4.5 and RCP 8.5 in the future. [ABSTRACT FROM AUTHOR]

Risk and vulnerability assessment of urban water systems can be extended to include several components. This work formulates a probable quantitative assessment of risk and vulnerability of urban water system based on climatic conditions and urban population growth. Climate change scenarios and population projections are used to estimate susceptibility to water supply systems’ risk and vulnerability. Quantile regression was used to establish the exponent correlation between the climate variables and population; and evaluate their consequential influences on urban water supply systems. We complemented the analysis with a probabilistic model to assess the robustness of urban water system that depends wholly on the climate for freshwater source. The study established that Climatic conditions, though uncertain, point to freshwater deficiency in the future. Moreover, population trends project a higher urban population thereby increasingly lowering water per capita and subsequently leading to doubtful urban water system’s resilience to the exogenous pressures. [ABSTRACT FROM AUTHOR]

Cities increasingly confront climate change-related problems of flooding, urban heat island effects, and the impact of drought on vegetation. There is a need for urban water and infrastructure planners to be able to identify vulnerable areas and to design, compare and evaluate interventions to address these problems. In response to this need, we developed the Integrated Climate Adaptation Model (ICAM), which is a Web-GIS tool based on a spatially explicit framework. ICAM has a user-friendly interface for use by a wide range of urban planning and design professionals. The tool is built on high-resolution spatial datasets, allowing users to identify critical areas that may be impacted by sea-level rise, drought, flooding, temperature increases and threats to tree heath and to consider the benefits of various grey and green infrastructure interventions. The tool is suitable for planning and evaluating interventions and to identify pathways for further desktop modelling. [ABSTRACT FROM PUBLISHER]

Water scarcity and flooding associated to climate variability and poor water use efficiency affect the liveability of our cities and their water security in the long term. As advocated by the Integrated Water Management (IWM) model, a transition towards arrangements that, besides centralized water infrastructures, also include onsite and efficient organization of water flows is required. A Landscape Elements Water Management Strategy (LEWMS) has been outlined to immediately guide the exploration of potential source control solutions for the recurrent spatial elements of a given urban landscape (roofs, gardens, parks, etc.) and the result of their reiteration at the catchment level. In the LEWMS, spatial configurations, water flow patterns and stakeholder’s arrangements generated by the spread of different decentralized options are drawn up to allow their comparison. Tested in the Brussels-Capital Region (BCR), the analysed macro effects of micro-scale landscape-based practices are gaining the attention of the local institutions. [ABSTRACT FROM AUTHOR]

Integrated water resources management (IWRM) was reviewed in the city of Melbourne. Melbourne performs well and shows a good level of commitment to sustainable solutions. The city scores highly in areas such as water efficiency, wastewater efficiency, i.e., energy recovery, and climate change commitments related to heat and water scarcity. Nearly 30% of houses in Melbourne have installed rainwater tanks and plans to increase the use of stormwater have recently been published. Energy efficiency of buildings, nutrient recovery (especially phosphate) from wastewater, as well as sewage sludge recycling are topics for improvement. A transparent governance structure has been set up in a reaction to the ‘Millennium Drought’ and success has come from many organizations working together to a common goal. This is the secret of Melbourne’s success and can be used as an example for other cities in the world. [ABSTRACT FROM PUBLISHER]

A solution is proposed to make use of the rainwater thermal energy in highly urbanised areas. It is demonstrated that the stormwater heat represents an additional on-site renewable energy available for hot water production. The proposed solution increases multi-functionality in the urban infrastructure that is essentially used to mitigate impacts from extreme climate events. The integrated system model applications correspond to local area conditions in the north-eastern Baltic region. This study considers the optimal collection of stormwater through maximizing the water absorbed heat usage in relation to hot water consumption in different building types (residential, public and commercial). Two key parameters, ‘stormwater volume in storage tank’ and ‘rainwater catchment area’, are determined. A genetic algorithm finds a number of storage tank fillings corresponding to rainfall statistics and the hot water consumption of buildings. System cumulative expenses are related to the stormwater storage and the rainwater harvesting expenses. [ABSTRACT FROM AUTHOR]

Urban development and climate change are expected to have significant effects on urban stormwater runoff. In this study, the Dynamic Urban Water Simulation Model (DUWSiM) is applied to Dublin, Ireland, to explore urban runoff patterns under varying urban growth and climate scenarios. Results show that annual urban runoff could decrease by 3.0% from climate change and monthly runoff could increase by 30% in winter and decrease by 28% in summer. Results also indicate that urban growth could increase annual runoff by up to 15%. The combined effect of climatic and land-use change generated runoff may potentially increase annual totals from between 2.9% to 21%. Monthly changes in runoff totals could increase by up to 57%. Accommodating these variations in runoff between the scenarios, flexible decentralised systems such as green roofs and pervious pavements, have a vital role in increasing the adaptability and long term sustainability of water infrastructure. [ABSTRACT FROM PUBLISHER]

We determined reference hydro-climatic and land use/cover sensitivities of stormwater runoff and quality in the Miami River Basin of Florida by developing a dynamic rainfall-runoff model with the EPA Storm Water Management Model. Potential storm runoff in the complex coastal-urban basin exhibited high and notably different seasonal sensitivities to rainfall; with stronger responses in the drier early winter and wetter late summer months. Basin runoff and pollutant loads showed moderate sensitivities to the hydrologic and land cover parameters; imperviousness and roughness exhibited more dominant influence than slope. Sensitivity to potential changes in land use patterns was relatively low. The changes in runoff and pollutants under simultaneous hydro-climatic or climate-land use perturbations were notably different than the summations of their individual contributions. The quantified sensitivities can be useful for appropriate management of stormwater quantity and quality in complex urban basins under a changing climate, land use/cover, and hydrology around the world. [ABSTRACT FROM AUTHOR]

Flooding often has devastating consequences. It is important to understand the evolution of these risks as climate changes. Municipal infrastructure is designed using historical data that no longer accurately represents current climate conditions, indicating infrastructure may underperform. The purpose of this study is to apply a new methodology for the assessment of climate change caused flood risk by Boweringet al.(2013) to the City of London, Ontario, Canada. Floodplain maps derived from climate, hydrologic and hydraulic analyses provide direct input into risk assessment procedure. Inundated infrastructure and high risk areas are identified in tables and maps for two climate and two hydraulic scenarios. Results indicate the most critical flood scenario is the 100 year climate change upper bound and high risk is driven by expensive infrastructure located in the floodplains. Results of the study are used as the support for climate change adaptation policy development and emergency management. [ABSTRACT FROM AUTHOR]

Water losses in pipe networks are usually the biggest ‘water use’ due to the high leakage occurring. The need for conservative water use is today more pressing than ever due to the stressful climate change conditions, forcing water utilities to consider applying effective Non Revenue Water reduction strategies. The assessment of a network's current operating status based on the IWA water balance (WB) is a good start. Although IWA suggests the WB to be annually assessed, this is not ideal for networks experiencing seasonal demand peaks, like in Kos town, capital of Kos Island in Greece. The WB for Kos town network was assessed on a bimonthly basis, following the water billing period used by the local water utility. The results revealed that higher real loss rates occur during the lower water demand periods due to the higher operating pressures. The annual WB can not reveal water loss peak timing. [ABSTRACT FROM AUTHOR]

In a study to identify strategies to deal with rapid urbanization and threatening climate change, in Can Tho City, Vietnam, a survey of 1200 households was undertaken to investigate water access and sanitation services. The survey targeted three different groups based on their access to water services: (a) those with piped water supply, (b) without piped water, and (c) a mix of (a) and (b). Socio-economic factors and level of urbanization significantly influenced the different water sources accessed by households and their type of sanitation. Results indicated that householders often employed multiple water sources in an attempt to match source with intended use. The use of multiple water sources, levels of sanitation and the quality of water were found to be good indicators of reported rates of illness. Results also showed that the provision of piped water does not always provide the desired health outcomes, as the definition of adequate water supply does not include water quality objectives. Therefore, more detailed assessments may be required to understand how people use and access water and sanitation, and the impacts on public health. [ABSTRACT FROM PUBLISHER]

Water distribution systems (WDSs) construction, operation and disposal processes contribute to undesirable greenhouse gas (GHG) emissions. GHG concentration in the atmosphere is strongly associated with global warming and climate change. In order to meet the consequent challenge of limiting GHG emissions, the problem of WDS (re)design is formulated here as a multi-objective optimisation problem. The three objectives are as follows: (1) minimisation of total (re)design cost, (2) maximisation of the WDS resilience and, (3) minimisation of GHGs emissions. In addition to the frequently considered conventional (re)design intervention options (new pipes, pipe duplication or replacement, addition of pumps, tanks, etc.), various water demand management interventions (e.g. water efficient appliances and domestic Rainwater Harvesting Systems) are considered here too. A number of different rainwater tank sizes and water saving appliances provided to different parts of the households have been evaluated. This methodology was applied on the New York Tunnels and the Anytown network problems. The output from the Non-dominated Sorting Genetic Algorithm (NSGA2) optimisation process is a Pareto front containing optimal solutions traded-off in terms of the three objectives analysed. The results obtained demonstrate that using demand management technologies in the (re)design of WDSs can lead to a similar cost, resilience and GHG emissions but with cost savings. In a pumped WDS where cost savings and GHG emission reduction are relatively significant, demand management technologies led to more cost effective, resilient and climate change mitigating solutions as compared to the conventional (re)design. [ABSTRACT FROM AUTHOR]

Extreme rainfall events that are occurring more frequently as an effect of climate change and variability are causing increasing damages to municipal infrastructure. A methodology is developed to quantify the risk to municipal infrastructure from climate change-related flooding. The risk is measured using a combination of flow/frequency, stage/damage and damage/frequency curves. The measure of risk is termed the Risk Index and calculated for each infrastructure element within a municipality. The risk is aggregated and summed by spatial unit and presented in the form of risk tables and maps. The risk index takes into account both quantitative and qualitative information obtained from research and interviews with technical experts. The results from the application of the methodology to a municipality will lead to better policy and informed decision making. [ABSTRACT FROM PUBLISHER]

Urban flood risk is increasing as a consequence of climate change and growing impervious surfaces. Increasing complexity of the urban context, gradual loss of tacit knowledge and decreasing social awareness are at the same time leading to inadequate choices with respect to urban flood risk management (UFRM). The European Flood Risk Directive emphasises the need for non-structural measures aimed at urban resilience and social preparedness. The Three Points Approach (3PA) provides a structure facilitating the decision making processes dealing with UFRM. It helps to accept the complexity of the urban context and promotes transdisciplinarity and multifunctionality. The 3PA introduces three domains wherein water professionals may act and where aspects valued by different stakeholders come into play: (1) technical optimisation, dealing with standards and guidelines for urban drainage systems; (2) spatial planning, making the urban area more resilient to future changing conditions; and (3) day-to-day values, enhancing awareness, acceptance and participation among stakeholders. Based on in-depth interviews conducted in The Netherlands and Denmark, we describe the complexity of decision making in practical UFRM and explain how the 3PA can be used when organising participatory processes. We introduce a theoretical framework characterising the large range of aspects involved in decision making related to UFRM and evaluate the usefulness of the 3PA in dealing with it. We conclude that the 3PA offers water managers and operators an efficient communication tool and thinking system, which helps to reduce complexity to a level suitable when organising strategy plans for UFRM and urban adaptation to climate change. [ABSTRACT FROM PUBLISHER]

Design of urban drainage structures should include the climatic changes anticipated over the technical lifetime of the system. In Northern Europe climate changes implies increasing occurrences of extreme rainfall. Three approaches to quantify the impact of climate changes on extreme rainfall are studied, all based on output from historical rain series of the present climate and output from Regional Climate Models. Two models are applied, one being based on an extreme value model, the Partial Duration Series Approach, and the other based on a stochastic rainfall generator model. Finally an approach is based on identification of areas, where the present climate resembles the anticipated future climate for the region in question. The results indicate that design intensities in Denmark are likely to be increased by 10–50% within the next 100 years. The increase in design intensities depend on the duration and the return period in question. [ABSTRACT FROM PUBLISHER]

Municipal Drinking Water Distribution Systems (MDWDSs) consume a significant quantity of energy to transport water, thereby exacerbating greenhouse gas emissions and global climate change. The current study is a sensitivity analysis that uses a network solver to quantify energy savings due to the alteration of three system properties—system-wide water demand, storage tank parameters (maximum water level, diameter, elevation), and pumping stations (horsepower, number of boosters, and their locations) of seven diverse MDWDSs. It was found that a 50% reduction in water demand, main pump horsepower, and booster horsepower resulted in an average energy savings of 47, 41, and 9.5% respectively, for the seven systems analyzed. Other properties examined showed insignificant savings. Even though an individual system analysis is more conclusive, this sensitivity analysis can guide optimization studies to focus on the most sensitive properties. [ABSTRACT FROM AUTHOR]

The present study examined the future of UK sewer systems at timescales, up to 2020 and to 2080. The most significant drivers for change were identified for different socio-economic and climate scenarios. A wide range of potential responses to these drivers were studied using the analysis of literature, expert workshops and limited modelling. The assessment of effectiveness of a number of these responses are presented and discussed. In the short to medium term it was shown that technological responses were most likely to be effective. In the longer-term controls on urbanisation and land use were seen to be more effective. [ABSTRACT FROM AUTHOR]