Estimation of household water end use in Trincomalee,Sri Lanka

This study estimates household water use in three localities in drought-prone Trincomalee, in the dry zone of Sri Lanka. Most of the water in the research area derives from taps, reservoirs and dug wells. This research used questionnaires and interviews to determine each end use and monthly usage of tap water. Household water is used mostly for bathing, washing clothes, vehicles and toilets. Despite the small sample size and the economic and social differences, these results correspond quite well to those found elsewhere.     

Urban versus regional--how public attitudes to recycled water differ in these contexts.

This paper reports findings from a comparative study which investigated public attitudes to recycled water in two Australian locations both in the state of Victoria: the capital city, Melbourne, and Bendigo, an urban regional centre. Two commercial buildings were used as case studies, one at each location. These buildings will soon be using recycled water for non-potable uses. The study was facilitated by an on-line survey of future occupants of both buildings to gauge their attitudes to recycled water use. Specifically the paper reports on happiness/willingness to use recycled water for various uses and attitudinal factors which were found to influence this. The circumstances for potable water availability and recycled water use differ in Melbourne and Bendigo, making this study a significant contribution to understanding public acceptance of recycled water use in these different contexts. No significant difference in happiness to use recycled water was found between locations. However, prior experience (use) of recycled water was found to be a significant and positive factor in facilitating happiness/willingness to use recycled water, particularly for closer to personal contact uses such as showering and drinking. Various attitudinal and demographic variables were found to influence happiness to use recycled water. Results indicate it is not just the locational context of water availability that influences happiness to use recycled water, but a person's experience and particular perceptions that will facilitate greater willingness to use recycled water.     

Guyana, “Land of Waters,” Moves to Harness Hydro Potential

ABSTRACT

Heavy metal concentrations (cadmium, chromium, lead, zinc) in 46 cistern water supply systems from single-family dwellings on St. Maarten, Netherlands Antilles were considerably below US drinking water limits in most cases. Release of zinc, lead, and cadmium in the distribution system, which is not related to the corrosiveness of the cistern water, caused lead and cadmium to exceed the US Public Health Service standard for 3 (6.5%) and 1 (2.2%) of the cisterns, respectively.

The following recommendations are suggested for protecting the roof catchment drinking water supply against heavy metal contamination:

? engineer the withdrawal of cistern water to exclude the metal-laden sediment

? identify appropriate paints to be used for cistern collection systems

? install substituted materials, protective coatings, and replacement of corroded metal parts in the distribution system

? discourage the usage of metal containers (e.g., oil) for prolonged water storage

? expand cistern water quality analyses to include lead

? exercise plumbosolvency control by treating the cistern water before distribution.

These recommendations, based on the case study, also apply to other areas of the world where cisterns of similar construction are used or are being planned.     

Determinants of Small-Area Water Consumption for the City of Phoenix,Arizona

Rapid population growth in the face of an uncertain climate future challenges the desert city of Phoenix, Arizona to consume water more prudently. To better understand the demand side of this important issue, we identified the determinants of water consumption for detached single-family residential units using ordinary least squares regression (OLS). We compared the results from the OLS model to those of a geographically weighted regression (GWR) model to determine whether there are spatial effects above and beyond the effects of the OLS variables. Determinants of residential water demand reflect both indoor and outdoor use and include household size, the presence of swimming pools, lot size, and the prevalence of landscaping that requires a moist environment. Results confirm the statistical significance of household size, the presence of a pool, landscaping practices, and lot size. Improvement of the GWR over the OLS model suggests that there are spatial effects above and beyond the effects for household size and pools – two of the four determinants of water demand. This means that census tracts exhibit water consumption behavior similar to neighboring tracts for these two variables. Model parameters can be used to investigate the effects of policies designed to regulate lot size, pool construction, and landscaping practices on water consumption and to forecast water demand in areas of new construction.     

Modelling Interactions Between Lot-Scale Decentralised Water Infrastructure and Urban Form – a Case Study on Infiltration Systems

Modelling the design and implementation of urban water infrastructure (particularly decentralised systems) for strategic planning and policymaking requires detailed information of the spatial environment and quantitative knowledge of social preferences. Currently available models, however, mostly use land use, population and impervious cover data without much regard for detailed urban form or society. This study develops an algorithm for determining urban form from minimal spatial data input by incorporating local planning regulations. The interaction between urban form and implementation of lot-scale infiltration systems under different social, biophysical and climate constraints is then investigated, firstly by looking at how this varies in different residential land uses and subsequently in a case study of a typical Melbourne residential subdivision of mixed land uses. Feasibility of infiltration and its downstream impact (runoff volume, frequency and pollution) were assessed for a range of social preferences (quantified as allowable garden space) and climate scenarios (30 % increase/decrease in rainfall and evapotranspiration). Performance indicators were determined through long-term simulation with the MUSIC software. Results show how different biophysical, planning, social and climate conditions affect infiltration feasibility as well as system performance. High infiltrating soils, for example, allow smaller, well-performing and socially less-imposing systems. Low infiltrating soils lead to larger system sizes, occupy much of the allotment’s garden space, but nevertheless provide the benefit of runoff frequency reduction. Overall, climate impact was not significant except for areas with poorly infiltrating soils. Joint consideration of social, planning, climate and water management aspects potentially allows more efficient policymaking, as an array of system configurations can be tested against different multi-faceted scenarios. Such models can help facilitate better participatory planning and policymaking.     

A combined stochastic dynamic programming-statistical disaggregation approach applied to multiple reservoir systems

The stochastic dynamic programming (SDP) method faces computational difficulties when used to determine the optimal operation of multiple storages. A new approach, a combined SDP-statistical disaggregation approach is introduced to determine releases for a special situation relating to multiple reservoir systems, that is, for a system of multiple storages where operational data are available. The approach consists of defining an equivalent single reservoir which represents the system of multiple reservoirs. The optimal releases from the equivalent single reservoir are derived by the use of SDP. Disaggregation of the optimal releases from the equivalent single reservoir, to produce the releases from the individual storages is based on historical operational data. The Melbourne (Australia) water supply system is considered as the example. The releases derived from the combined SDP-statistical disaggregation approach are tested by operating a simulation model, and the conclusion is made that the approach produces satisfactory releases for a system of multiple reservoirs where operational data are available. The method cannot be applied to existing systems where insufficient or no operational data are available, or to proposed systems where operational data are not available. The method uses a small amount of computer time.     

Performance Analysis of a Communal Residential Rainwater System for Potable Supply: A Case Study in Brisbane, Australia

Cities in developed countries have increasingly adopted rainwater tanks as an alternative water source over the last 15 years. The rapid uptake of rainwater tanks has been driven by the need to reduce demand for centralised water services that are under pressure to adapt to population growth and climate change impacts. Rainwater tanks are part of integrated urban water management approach that considers the whole water cycle to provide water services on a fit for purpose basis that minimises the impact on the local environment and receiving waters. Rainwater tanks are typically applied at the household scale for non-potable water source uses such as toilet flushing and garden irrigation. However, this paper reports on a communal approach to rainwater harvesting, where the water is treated for potable use. A communal approach to rainwater harvesting can offer benefits, such as: economies of scale for capital costs, reduced land footprint, centralised disinfection and flexibility in matching supply and demand for different households. The analysis showed that the communal approach could provide a reliable potable water source to a small urban development. However, there was an energy penalty associated with this water source compared to centralised systems that could be addressed through more appropriate pump sizing. The outputs from this monitoring and modelling study demonstrated rainwater harvesting can be expanded beyond the current mainstream practices of household systems for non-potable use in certain development contexts. The analysis contained in this paper can be used for the improved planning and design of communal approaches to rainwater harvesting.     

Environmental and Resource Costs Under Water Scarcity Conditions: An Estimation in the Context of the European Water Framework Directive

The European Water Framework Directive (WFD) requires the good ecological status of surface water bodies, which implies the improvement of both their physicochemical condition, as well as their flow and continuity. The WFD prescribes the assessment of environmental and resource costs and benefits associated with implementing these improvements. The recent literature focuses almost exclusively on the assessment of the economic values related to quality aspects. However, in much of southern Europe, fulfilling the WFD goals will greatly depend on maintaining sufficient water flow, as well. This study aims to fill this gap by assessing the non-market value of allocating enough water to the environment to ensure environmental services are sustained when water is scarce. The non-market value of guaranteeing water supply for secondary household uses is also estimated. Using the Guadalquivir River Basin in Spain as a case study, a choice experiment is applied with scenarios characterized by varying water flow levels and accompanying environmental impacts, and a different frequency of household water restrictions. The results show that the population derives significant benefits not only from the direct use of water, but that also holds non-use values related to the ecological status, although the latter has a considerably lower impact on consumer surplus. Additionally, we conclude that the costs of implementing the water saving measures currently included in the Program of Measures seem to be proportionate to its benefits in this case.     

Pushing the Governance Boundaries: Making Transparent the Role of Water Utilities in Managing Urban Waterways

Integrated Water Resource Management (IWRM) requires simultaneous consideration of the multiple benefits that attend water. IWRM can also be more challenging in regulatory environments where the resource manager must justify choices and elements of each intervention. This is particularly challenging in the context of urban waterways that have many uses including an ecological function and a source of human amenity. To justify expenditure on maintaining and improving urban waterways for ecological and/or amenity changes regulated utilities must be able to articulate and measure these types of values with at least some degree of precision. This paper presents a generic and systematic framework for understanding the ecological and amenity values of urban waterways. We illustrate deployment of the framework in the case of Melbourne, one of Australia’s fastest growing cities and a location ranked as amongst the most liveable since 2011. We also explore how the results could improve the way we measure benefits in dollar terms.     

A Desktop Analysis of Potable Water Savings from Internally Plumbed Rainwater Tanks in South-East Queensland,Australia

A methodology for the estimation of household potable water saving due to internally plumbed rainwater tanks (IPT) is presented in this paper. The methodology is based on a pairwise comparison of household water billing data between homes with IPT and without rainwater tanks (No Tank). These savings were compared with estimations using measured end use data and rainwater demand predictions using the Rainwater TANK model. The paper describes the application of this methodology to a case study in the south-east Queensland (SEQ) region of Australia. There was a significant reduction in mains water consumption for IPT properties in all regions studied in SEQ. Water reductions from mains supplies varied markedly across regions with mean values ranging from 20 to 95 kL/hh/y with an average mean of 50 kL/hh/y. Median water consumption values, ranged in mains water reductions from 28 to 52 kL/hh/y, with an average median of 40 kL/hh/y. Considering both measures an average water saving between 40 and 50 kL/hh/y can be expected from internally plumbed rainwater tanks. Water restrictions appear to have a strong influence on estimated reductions in mains water use. In regions where water restrictions were severe, water consumption was less varied between No Tank and IPT homes with a consequent reduction in estimated savings observed. Recommendations for further work include a survey to capture confounding factors that could not be fully controlled in the desktop study and a controlled pairwise experiment to monitor water consumption from raintanks.     

Development of an intelligent model to categorise residential water end use events

The aim of this study was to disaggregate water flow data collected from high resolution smart water meters into different water end use categories. The data was obtained from a sample of 252 residential dwellings located within South East Queensland (SEQ), Australia. An integrated approach was used, combining high resolution water meters, remote data transfer loggers, household water appliance audits and a self-reported household water use diary. Disaggregating water flow traces into a registry of end use events (e.g. shower, clothes washer, etc.) is predominately a complex pattern matching problem, which requires a comparison between presented patterns and those contained with a large registry of categorised end use events. Water flow data collected directly from water meters includes both single (e.g. shower event occurring alone) and combined events (i.e. an event which comprises of several overlapped single events). To identify these former mentioned single events, a hybrid combination of the Hidden Markov Model (HMM) and the Dynamic Time Warping algorithm (DTW) provided the most feasible and accurate approach available. Additional end use event physical context algorithms have been developed to aid accurate end use event categorisation. This paper firstly presents a thorough discussion on the single water end use event analysis process developed and its internal validation with a testing set. This is followed by the application of the developed approach on three independent households to examine its degree of accuracy in disaggregating two weeks of residential flow data into a repository of residential water end use events. Future stages of algorithm development and testing is discussed in the final section.     

Quality matters: incorporating water quality into water access monitoring in rural Malawi

The Sustainable Development Goals offer an ambitious plan to achieve universal access to water that is safe and affordable. This article uses data from 139 household surveys from 13 villages in rural Malawi and Petrifilm quality testing of 27 drinking water sources to highlight areas where the goals’ proposed monitoring framework might not fully capture water quality. Households make complex water decisions and sometimes choose to use unsafe sources. Households generally do not use water treatment but universally practise water storage. This article argues for improved monitoring to more effectively and accurately measure sustainable water access.     

Modelling to assist in wastewater collection system odour and corrosion potential evaluations.

Odour emissions and corrosion concerns can be a constant focus for many wastewater treatment and collection system owners, usually from the first day that their collection systems begin operation. Many sewer systems are reaching the end of their useful life, or have experienced either odour or corrosion issues. This paper shows a link between odour generation and corrosion potential, and how modelling can be used to assist in odour/corrosion assessments of existing wastewater collection systems. A model has been developed that is capable of predicting liquid-phase sulphide generation and subsequent release to overlying sewer headspace as hydrogen sulphide (H2S), where it can be the source of either odour or corrosion problems. This paper presents an overview of the model, and uses a case study involving both odour and corrosion issues to demonstrate the utility in modelling. The model was used to identify potential locations within the system where odour/corrosion may be problematic, as well as assisting in the evaluation of potential odour control alternatives.     

Assessment of impact of water diversion projects on ecological water uses in arid region

In arid regions, large-scale water diversion from rivers leads to significant changes in river flow regimes, which may have large impacts on ecological water uses of river-dependent ecosystems, such as river, lake, wetland, and riparian ecosystems. To assess the integrated impact of water diversion on ecological water uses, we proposed a hierarchy evaluation model composed of four layers representing the evaluation goal, sub-areas of the influenced region, evaluation criteria, and water diversion schemes, respectively. The evaluation criteria for different types of ecological water uses were proposed, and the analytical hierarchy process was used for the integrated assessment. For a river ecosystem, the percentage of mean annual flow was used to define the grade of environmental flow. For a lake ecosystem, water recharge to the lake to compensate the lake water losses was used to assess the ecological water use of a lake. The flooding level of the wetland and the groundwater level in the riparian plain were used to assess the wetland and riparian ecological water uses, respectively. The proposed model was applied to a basin in northern Xinjiang in northwest China, where both water diversion and inter-basin water transfer projects were planned to be carried out. Based on assessment results for the whole study area and two sub-areas, an appropriate scheme was recommended from four planning schemes. With the recommended scheme, ecological water uses of the influenced ecosystems can be maintained at an acceptable level. Meanwhile, economical water requirements can be met to a great extent.     

基于分级响应机制的家庭智慧节水系统设计

由于住户每次用水的时间和用水量是不可预知的,所以能够灵活应对这种不确定性因素的响应安排就显得尤为重要。提出了一套基于分级响应机制的家庭智慧节水系统,该系统在分级响应的基础上,结合ZigBee无线网络和Android智能平台,实现了对家庭用水数据的实时监测与用水设备的远程控制。传感器采集用户家中用水数据,通过Zig Bee无线组网方式进行数据收发,服务器作为整套系统的大脑,根据本文提出的分级响应机制对来自终端节点的用水数据进行处理并分析,根据不同的分析结果选择不同的响应级别进而采取不同的控制措施。介绍了系统的总体设计方案以及分级响应机制的内容,并利用RBF神经网络对分级响应机制进行优化,最后通过案例分析论证了该系统对节约家庭用水能够起到较为明显的效果。     

Quantifying and managing urban water-related energy use systemically: case study lessons from Australia

Abstract

In this paper, three Australian case studies contribute to improved understanding of water-related energy quantification and management. A systems analysis of urban water in South East Queensland (Case Study 1) demonstrates the energy impact of water end use. In Melbourne (Case Study 2), water–energy interlinkages are explored within households. Finally, Case Study 3 in Sydney shows how abatement curves can help guide management action. Collectively, the case studies provide new information for least-cost solutions and simultaneous water and energy efficiency. The work highlights the need for frameworks to characterize and evaluate both the direct and indirect energy influences of urban water.     

Capturing the complexity of water uses and water users within a multi-agent framework

Due to the hydrological and socio-economic complexity of water use within river basins and even sub-basins, it is a considerable challenge to manage water resources in an efficient, equitable and sustainable way. This paper shows that multi-agent simulation (MAS) is a promising approach to better understand the complexity of water uses and water users within sub-basins. This approach is especially suitable to take the collective action into account when simulating the outcome of technical innovation and policy change. A case study from Chile is used as an example to demonstrate the potential of the MAS framework. Chile has played a pioneering role in water policy reform by privatizing water rights and promoting trade in such rights, devolving irrigation management authority to user groups, and privatizing the provision of irrigation infrastructure. The paper describes the different components of a MAS model developed for four micro-watersheds in the Maule river basin. Preliminary results of simulation experiments are presented, which show the impacts of technical change and of informal rental markets on household income and water use efficiency. The paper also discusses how the collective action problems in water markets and in small-scale and large-scale infrastructure provision can be captured by the MAS model. To promote the use of the MAS approach for planning purposes, a collaborative research and learning framework has been established, with a recently created multi-stakeholder platform at the regional level (Comisión Regional de Recursos Hidricos) as the major partner. Finally, the paper discusses the potentials of using MAS models for water resources management, such as increasing transparency as an aspect of good governance. The challenges, for example the need to build trust in the model, are discussed as well.     

Irrigation Modelling in the Context of Basin Water Resources

Management practices for irrigation schemes can often be improved by modelling the behaviour of a scheme and by evaluating its efficiency statistics. However, looking at an irrigation scheme without regard for other water uses within the river basin may not be effective. Efficiencies computed in this way are local and, since water may be used many times within the same basin, may not be realistic. Changes in water uses (e.g. irrigation, industrial, power production, urban water supply, navigation, environmental, recreational) will often have effects on other uses; and changes in irrigation schemes (management,structural, crop pattern) may affect other users within the basin. In addition, all water users will be affected by external changes such as changes in land cover or in climate. As demand for water increases, these links become more important until, at some stage, there is insufficient water for all users and hard choices must be made. Hydrological modelling is a tool that can be used to relate irrigation schemes to the other water uses within a river basin and can help in assessing real productivities and in evaluating alternative patterns of water usage. This paper discusses the techniques available to simulate irrigation schemes within overall basin water resources using, as an example, an intensively utilized basin in western Turkey.     

In-house contamination of potable water in urban slum of Kolkata, India: a possible transmission route of diarrhea

We have investigated and determined the potentiality of different water sources, both for drinking and domestic purposes, in diarrheal disease transmission in diarrhea endemic foci of urban slums in Kolkata, India in a one and half year prospective study. Out of 517 water samples, collected from different sources, stored water (washing) showed higher prevalence of fecal coliforms (58%) (p < 0.0001) in comparison with stored (drinking) samples (28%) and tap/tubewell water (8%) respectively. Among different sources, stored water (washing) samples had the highest non-permissible range of physico-chemical parameters. Fecal coliform levels in household water containers (washing) were comparatively high and almost 2/3 of these samples failed to reach the satisfactory level of residual chlorine. Interestingly, 7% stored water (washing) samples were found to be harboring Vibrio cholerae Improper usage of stored water and unsafe/poor sanitation practices such as hand washing etc. are highlighted as contributory factors for sustained diarrheal episodes. Vulnerability of stored water for domestic usage, a hitherto unexplored source, at domiciliary level in an urban slum where enteric infections are endemic, is reported for the first time. This attempt highlights the impact of quality of stored water at domiciliary level for fecal-oral contamination vis-à-vis disease transmission.     

Supplementing urban water supply with rainwater harvesting in Accra,Ghana

This article examines the challenges associated with rainwater harvesting and usage in peri-urban Accra. Data collected from 357 heads of household reveal that rainwater harvesting has the potential to supplement existing water sources in peri-urban Accra. However, high investment costs for rainwater harvesting facilities, short-term tenancy arrangements, the perception that rainwater is not clean, and the unique dry climate of the Accra Plains emerge as key challenges limiting domestic use of rainwater. Public education for house owners to invest in rainwater harvesting facilities and governmental support will be needed to increase investment in rainwater harvesting, purification and usage.