Urban water management strategies based on a total urban water cycle model and energy aspects – Case study for Tel Aviv

Global change pressures such as climate change, water scarcity, population growth, full urbanisation of catchments and rising energy costs may increasingly affect the urban water system of Tel Aviv. These challenges formed the incentive for a multidisciplinary Learning Alliance of water sector institutions to embark on a process to identify ways to improve sustainability of the city's water system. Sustainability indicators were identified and a whole-of-system water balance model (AquaCycle) was used to score the indicators for future scenarios and strategies. Strategies included rainwater harvesting, stormwater use, permeable pavements, and wastewater reuse. The effect of the strategies on total water imported into the city was a reduction of 10% by rainwater harvesting and 32% by wastewater reuse at cluster scale. The latter strategy reduced energy consumption from 2.89 kWh per m³ of volume of water used (import + reuse) in the current situation to 2.45 kWh per m³.     

An ecosystemic approach for assessing the urban water self-sufficiency potential: lessons from the Mediterranean

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.     

适宜残疾人使用的城市公园设计探析

针对残疾人的心理及行为活动特征,阐述了适宜残疾人使用的城市公园的设计原则,同时从声景及香景的营造、色彩的运用、触觉及线路的设计几个方面总结了公园的设计内容,从而设计建造出适宜残疾人使用的城市公园。     

Sustainable strategies on water supply management in Hong Kong

The growth in population and of the economy of Hong Kong has caused a significant increase in the demand for fresh water. To secure sufficient water supply and to reduce reliance on imported water from Dongjiang (East River) in Mainland China, the Hong Kong Special Administration Region (HKSAR) government has implemented a wide range of water conservation measures which include the use of seawater for toilet flushing, metering and a tiered water tariff, large‐scale replacement and rehabilitation of ageing pipelines to reduce leakage, valve‐type toilet flushing apparatus and education and publicity programmes. To ensure sustainable and safe water supply, the HKSAR government is actively exploring alternative water resources including the treated effluent from sewage treatment plant, desalination of seawater and the extension of water‐gathering grounds in the territory.     

Potential of rainwater resources based on urban and social aspects in Colombia

The potential offered by non‐conventional water resources (rainwater) associated with high or low urban density in new housing in different rainfall zones (800–2300 mm) was studied. Ten cities in Colombia with over 250 000 inhabitants were used as a case study. The potential of substitution of tap water by rainwater according to population groups with different socioeconomic status was estimated. This study reveals the favourable conditions for rainwater harvesting in the Colombian context, and enables the linking of supply and demand issues related to local climatic and environmental sustainability in order to integrate the use of rainwater into urban housing projects. For the current consumption scenario (greater than 160 Lcd), rainwater becomes a potential replacement for mains water in urban areas with rainfall of above 1553 L/m²/year.     

赣州市城市公园的结构与布局研究

通过对赣州市城市公园等级结构与空间布局的现状分析研究,指出了该市公园布局存在的问题,并进一步提出优化布局的建议,以期改善赣州市城市公园布局,完善公园级配和功能,从而提高该市公园的吸引力。     

The evolution of urban water systems: societal needs,institutional complexities,and resource costs

ABSTRACT

Urban water systems provide critical services to meet the supply, sanitation, and drainage needs of urban societies. Evolving needs have resulted in increasingly expansive infrastructure, raising questions about the sustainability of such large infrastructure investments. In this study, we demonstrate the historical interplay between growing urban water needs, the services developed to meet them, and their total resource cost. We hypothesize that needs evolve hierarchically, with predictable outcomes in the form of service progression. To test this hypothesis, we use a suite of metrics at the US national scale indicative of our proposed hierarchy levels. At the city scale, we assess the cost implications of this progression of services. We use the emergy framework to quantitatively reconstruct the historical resource requirements of supply, sanitation, and drainage services and show how evolving needs lead to mounting resource costs. Lastly, we discuss implications of continually increasing complexity for meeting future water needs.     

Decentralized water management: rainwater harvesting and greywater reuse in an urban area of Beijing,China

Large-scale centralised wastewater treatment system has often prevailed in industrial countries, and has been regarded as a successful approach during the last century. However, transfer of this highly water-consuming system and so-called ‘end-of-pipe’ technology to developing countries, especially in fast-growing cities with scarce water resources, has been extremely limited. Decentralized water treatment is not a new technology and has been successfully implemented in many rural areas worldwide. However, there are few applications in urban areas. This study at Tianxiu Garden in Beijing, China, investigated the potential and feasibility of water management based on a decentralized approach, but modified for application of greywater recycling and rainwater harvesting in a densely populated semi-urban area. A high degree of drinking water substitution (more than 25%) could not be attained by rainwater harvesting. Recycling of treated greywater for toilet flushing was shown to be an efficient method for minimisation of drinking water consumption, and a more suitable technique than rainwater harvesting for saving water in Beijing, China.     

Spatial and numerical analysis of the parameters influencing potential for potable water savings made using rainwater harvesting: case of the Paris agglomeration

The quantity of Potential for Potable Water Savings (PPWS) made using rainwater harvesting differs between municipalities within the same region. Three main parameters contribute to this difference: roof area, the number of inhabitants and rainwater use scenarios. This article proposes a spatial and numerical analysis of how these parameters influence PPWS across municipalities in the Paris agglomeration. A comparison between the location of the municipalities, the PPWS value and the values for the previous parameters was used to understand the observed difference. The spatial analysis shows that municipalities (districts) in the Paris have the highest PPWS values, on the contrary, the peripheral municipalities in the outer suburbs have the lowest PPWS values and the results for the intermediary municipalities—in the inner suburbs—are contrasting. The numerical analysis demonstrates a strong correlation between the main parameters influencing the PPWS value; where a high value for the “roof area” means a high value for the “number of inhabitants” and a good mix of rainwater “use scenarios,” and vice‐versa. In conclusion, the planning and design of the municipality—building density, types of buildings, number of inhabitants, the city's vocation—are key factors in defining the level of PPWS made using rainwater harvesting.     

Quantitative microbial risk assessment with respect to Campylobacter spp. in toilets flushed with harvested rainwater

In light of increasing pressures on water supplies in some areas, water demand management and water conservation techniques are likely to become increasingly prevalent. In‐house systems using alternatives to mains supplies for nonpotable uses present one such option for reducing potable water demand. This paper, through a formal desk‐based health impact assessment (HIA) and quantitative microbial risk assessment (QMRA), examines one of the possible health implications (Campylobacter infection from toilet flushing) resulting from the use of rainwater harvesting in the home in the United Kingdom. This is investigated using data from the literature and a hypothetical case study population of over 4000 people (based on data for the ‘average’ population in England), with the results being expressed as disability‐adjusted life years (DALYs) (on an annual basis) and placed in context of the ‘tolerable’ risk from drinking‐water supplies.     

Towards sustainable urban water management: A critical reassessment

Within the literature, concerns have been raised that centralised urban water systems are maladapted to challenges associated with climate change, population growth and other socio-economic and environmental strains. This paper provides a critical assessment of the discourse that surrounds emerging approaches to urban water management and infrastructure provision. As such, ‘sustainable urban water management’ (SUWM) concepts are scrutinized to highlight the limitations and strengths in the current lines of argument and point towards unaddressed complexities in the transformational agendas advocated by SUWM proponents. Taking an explicit infrastructure view, it is shown that the specific context of the urban water sector means that changes to infrastructure systems occur as an incremental hybridisation process. This process is driven by a range of factors including lock-in effects of legacy solutions, normative values and vested interests of agents, cost and performance certainty and perceptions of risk. Different views of these factors help explain why transformational agendas have not achieved the change SUWM proponents call for and point to the need for a critical reassessment of the system effects and economics of alternative service provision models.     

Beyond the public–private controversy in urban water management in Spain

This paper critically analyzes the Spanish privatization model of urban water management implemented over the last three decades. The high concentration of private participation in the industry, the absence of competition, and regulatory deficiencies appear to have put the interests of water customers at risk. Improvement of governance is not guaranteed simply by changing water-system management from public to private. In Spain, an array of institutional reforms are needed to rationalize a change in management structure for this service, reorganize technical operations, improve the administrative framework, increase transparency, and promote citizen participation. This paper moves beyond the simple public–private controversy and contributes to the literature by using fieldwork conducted by the authors to assess private participation in the management of urban water services in Spain; by identifying gaps in the privatization processes as well as failures in the industry; and, above all, by proposing reforms to Spain's institutional and regulatory frameworks for the industry.     

The management of urban surface water drainage in England and Wales

Partly in response to the UK flooding events of 2007, a number of reports have recently been produced addressing the legislative, administrative, institutional and structural practices that are required to improve urban surface water management and hence reduce future flooding incidents and associated pollution impacts. This paper addresses the principal barriers to progress that have been identified and how these are likely to be overcome. Improved and integrated organisational structures, process and procedures are required and relationships between flood risk management and water quality need to be addressed at regional, area and local levels as well as legislative clarification on surface water discharges. Nontechnical aspects will need to be supported by new modelling approaches for flood risk prediction at both local and catchment scale with effective communication systems and tools being developed and implemented for full and effective stakeholder participation.     

Physicochemical and microbiological quality of water from a pilot domestic rainwater harvesting facility in Ireland

Dublin Institute of Technology personnel were commissioned in 2005 by the Department of Environment, Heritage and Local Government in Ireland to assess the feasibility of utilizing harvested rainwater to replace treated mains water, for nonpotable uses. A pilot project was set up. The project involved the design, installation, commissioning and monitoring of rainwater harvesting facilities in a rural housing development. A monitoring programme was carried out to examine the physicochemical and microbiological quality of the harvested rainwater. Harvested rainwater was sampled monthly and tested. Analysis of the harvested rainwater quality showed a consistently high quality of raw water in general compliance with the requirements of the European Communities (Quality of Bathing Water) Regulations for 100% of samples and the European Communities (Drinking Water) Regulations, 2007 for 37% of sampling dates.     

Rainwater harvesting for human consumption and livelihood improvement in rural Nepal: benefits and risks

Use of rooftop rainwater as a source of drinking water in developing countries is increasing. However, scepticism about the potential of this source and the associated health risks is still prevalent among water planners. A free listing and a household survey among 120 households was conducted in the hills of Nepal to examine the performance of rainwater harvesting systems. Users perceive few health risks and in contrast, reported a wide range of benefits, including health benefits associated with the consumption of rainwater. Water quality testing results generally demonstrate good water quality but confirm that appropriate operation and maintenance practices are critical to ensure the collection of good quality water. Deficiencies in technical design and construction, lack of awareness, no market for spare parts and the inability of vulnerable households to maintain the system pose a risk to the collection and storage of safe water and to the long‐lasting performance of the systems.     

Review of multi-criteria decision aid for integrated sustainability assessment of urban water systems

Integrated sustainability assessment is part of a new paradigm for urban water decision making. Multi-criteria decision aid (MCDA) is an integrative framework used in urban water sustainability assessment, which has a particular focus on utilising stakeholder participation. Here MCDA is reviewed in the context of urban water management used in a decision making framework. Three other commonly used integrated approaches in urban water management (cost-benefit analysis, triple bottom line and integrated assessment) are compared with MCDA. Generic types of shortcomings associated with MCDA are discussed to provide an understanding of MCDA's limitation in urban water management decision making; including 1) preferential independency, 2) double counting and under-counting, and 3) transparency of MCDA methods and results.     

A decision support tool for sustainable planning of urban water systems: Presenting the Dynamic Urban Water Simulation Model

Population growth, urbanisation and climate change represent significant pressures on urban water resources, requiring water managers to consider a wider array of management options that account for economic, social and environmental factors. The Dynamic Urban Water Simulation Model (DUWSiM) developed in this study links urban water balance concepts with the land use dynamics model MOLAND and the climate model LARS-WG, providing a platform for long term planning of urban water supply and water demand by analysing the effects of urbanisation scenarios and climatic changes on the urban water cycle. Based on potential urbanisation scenarios and their effects on a city's water cycle, DUWSiM provides the functionality for assessing the feasibility of centralised and decentralised water supply and water demand management options based on forecasted water demand, stormwater and wastewater generation, whole life cost and energy and potential for water recycling. DUWSiM has been tested using data from Dublin, the capital of Ireland, and it has been shown that the model is able to satisfactorily predict water demand and stormwater runoff.     

Maximising the benefits of rainwater harvesting technology towards sustainability in urban areas of South Africa: a case study

ABSTRACT

Rainwater harvesting (RWH) technology has been in use for a long time, however its contribution towards urban water supply has been negligible in South Africa. Through a comprehensive literature review and analysis of interviews with key stakeholders, this case study presents implementation challenges and policy gaps in relation to the scale of adoption in the City of Johannesburg (CoJ). Findings show that only 0.1% of CoJ’s population utilises RWH due to various reasons, varying from financial viability, reliability, quality concerns, and system maintenance. This paper attributes these to the scale of adoption and suggests upscaling the system to larger commercial buildings to optimise benefits. However, there is an urgent need to bridge the policy gaps for successful implementation. Three categories of policy reforms are therefore proposed to facilitate innovation uptake, stakeholder engagement and compliance. This knowledge can guide future research towards urban water management, scientists and policymakers nexus.     

Smart meter enabled disaggregation of urban peak water demand: precursor to effective urban water planning

The implementation of a smart water metering system in Hervey Bay in 2006–2007 allowed the local water utility to record the hourly water consumption of all its customers. This data availability has enabled a large scale research project to proceed with the aim to disaggregate peak hour, peak day and peak month demand in the water distribution network into primary indoor usage (e.g. shower, washing machine, etc.) and irrigation components. Such information can guide the development of alternative tariff structures and other demand management initiatives aimed at reducing peak demand. This paper details results of the analyis of average hour, peak hour, peak day and peak month consumption data of 2884 residential customers selected from four District Metered Areas (DMAs) located in the city of Hervey Bay in Queensland, Australia.     

An ARIMA-NARX hybrid model for forecasting urban water consumption (case study: Tehran metropolis)

ABSTRACT

In this research, an ARIMA-NARX (Autoregressive Integrated Moving Average-Nonlinear Auto-Regressive eXogenous) hybrid model is proposed to forecast daily Urban Water Consumption (UWC) for Tehran Metropolis. The linear and nonlinear component of the UWC was forecast by ARIMA as a linear forecasting model and the artificial neural network as a nonlinear forecasting model, respectively. An alternative hybrid model including sunshine hour in addition to the previous studies’ predictors (the minimum, maximum and average temperature, relative humidity and precipitation) was selected as the superior alternative model. Then, the performance of proposed model was compared with ARIMA and NARX models. The results showed that the hybrid model, which benefits from capability of both linear and nonlinear models, has a higher accuracy than the other two models in forecasting UWC. Therefore, the proposed hybrid model has better results in UWC forecasting and, as a consequence, better urban water reservoir management will be provided.