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.     

Estimating Water Rights Demand and Supply: Are Non-market Factors Important?

Water rights demand and supply in the upper Maipo river basin (Metropolitan Region of Chile) are estimated for the period July 1998 to June 2003, as well as a reduced form model for the equilibrium water rights price based on supply and demand determinants, as well as characteristics of the participating agents such as the economic sector of each agent and their individual market experience. Results show that the main participants in the market are both agriculture and real estate sectors (developers); agriculture buying 57 % and selling 68 % of transactions. The estimated supply and demand system shows that market forces indeed drive market water right prices. Demand is inelastic to price while supply is highly elastic. Furthermore, supplied and demanded water rights quantities are functions of water right price as well as the economic sector of buyer and sellers, sectoral profits, and geographic location of the water right. Additionally, the agent’s previous water rights market-experience is an important determinant of water rights demands and supply.     

Modelling and control strategy testing of biological and chemical phosphorus removal at Aved?re WWTP.

The biological phosphorus removal process is often implemented at plants by the construction of an anaerobic bio-p tank in front of the traditional N removing plant configuration. However, biological phosphorus removal is also observed in plant configurations constructed only for nitrogen removal and simultaneous or post-precipitation. The operational experience with this "accidental" biological phosphorus removal is often mixed with quite a lot of frustration, as the process seems to come and go and hence behaves quite uncontrollably. The aim of this work is to develop ways of intentionally exploiting the biological phosphorus process by the use of instrumentation, control and automation to reduce the consumption of precipitants. Means to this end are first to calibrate a modified ASM2d model to a full-scale wastewater treatment plant (WWTP), including both biological and chemical phosphorus removal and a model of the sedimentation process. Second, based on the calibrated model a benchmark model is developed and various control strategies for biological phosphorus removal are tested. Experiences and knowledge gained from the strategies presented and discussed in this paper are vital inputs for the full-scale implementation of a control strategy for biological phosphorus removal at Aved?re WWTP, which is described in another paper. The two papers hence show a way to bridge the gap from model to full implementation.     

Why a Water Soft Path,Why Now and What Then?

The best way to achieve a sustainable future for fresh water is to develop decision-making processes, institutions, and technologies that emphasize both efficiency and conservation. These two terms are commonly treated as synonyms, but, respectively, they reflect anthropogenic and ecological bases for making decisions. Recognizing that both perspectives are valid, this article outlines a new approach to water planning and management called the water soft path. This approach differs fundamentally from conventional, supply-based approaches. The article reviews the transfer of the original soft path concept from energy to water, and summarizes the first applications of water soft path analytics to specific geographic areas: one urban area, one province, and one watershed in Canada. The article concludes with suggestions for further research, as well as steps to improve recognition of the water soft path as a planning tool that can move management and policies towards economic, ecological, and social sustainability.     

Water productivity and water footprint: misguided concepts or useful tools in water management and policy?

Water productivity (WP) and water footprint (WFP) are popular concepts in research and discourses on water management. Yet there are concerns about their theoretical validity and practical value. This paper shows that the water production function, the concept with a sound theoretical foundation, is the basis for WP. Total WFP is the reciprocal of WP. The practical value of WP and WFP depends on the context of water use and stress. Maximizing WP, not a panacea to all water problems, mainly suits arid rainfed areas. In other regions, economic and marginal WP for increasing overall production should take precedence in water management and policy decisions.     

How Do Residents Respond to Price under Increasing Block Tariffs? Evidence from Experiments in Urban Residential Water Demand in Beijing

Economic theory generally assumes that consumers respond to marginal price, which is the price of the last unit of goods consumed, when making economic decisions. However, this assumption may not hold for goods with multi-block rate schedules. This paper explores the effects of water price information on residents’ behaviors under increasing block tariffs. The empirical evidence from the study suggests the middle-income groups respond to average price, which is based on the price level given by total fees divided by total consumption. This evidence supports the hypothesis that the incremental block tariffs are actually treated the same as uniform pricing for the middle-income group, while the highest income group is not sensitive to price changes. On the contrary, residents of the two lowest income groups respond to marginal price and probably go further to compare prices of different blocks and set consumption at kink points of price schedules to achieve maximal welfare. This study also finds that a higher second block price promotes consumption at kink points, and increased payments in first block consumption lead to less incentive to induce discrete choice behavior.     

Introduction: Water for Food and Ecosystems: How to Cut which Pie?

Two decades of awareness-raising and dialogues have clearly spelled out the water-related challenges the world is facing. Still, not enough concrete improvements have been realized on key issues, such as the coverage of potable water and sanitation services, and an adequate balance between water for food and ecosystems. Addressing these problems remains a continuous challenge that can only be confronted with an integrated approach, comprising knowledge generation, permanent communication between very different stakeholders, adequate capacity-building and continuous learning, and innovative technology development. With a view to the Fourth World Water Forum in Mexico, this contribution reviews such issues, drawing lessons from experience in a program on Water for Food and Ecosystems (funded by Netherlands Partners for Water initiative) and related on-going work in this area carried out by Wageningen University and Research Centre working closely with partner institutions inside and outside the Netherlands. The debate is structured around three key dimensions (i) balancing human and natural values of water, (ii) multiple stakeholder involvement, (iii) technological innovation. Visualized in the Triangle of Sustainability, the study recognizes the advances made in integrating political processes such as multi-stakeholder negotiation in water resource management as a way of achieving a better balance between the values of water, but warn against neglecting the potential for technical advances that can help increasing the size of the ‘cake’ as a whole.     

Who joins advocacy organizations? Water quality and participation in rural shoreline Great Lakes communities

Civic organizations play an important role in translating individual preferences into the emergence of collective action for protection of the environment. The purpose of this article is to examine factors that help explain why individuals become aware of, and to ultimately join, local environmental advocacy groups. We conducted a mail survey of property owners in four slow growing, politically conservative rural watersheds along the southeast corner of Lake Ontario, inquiring about length of property ownership, engagement in outdoor activities, observations of impaired water quality, level of concern about the watershed environment, and awareness of and membership in local environmental organizations. We used two binary logistic regressions and find that owning property on the waterfront and length of tenure strongly predicts both awareness of and membership in stewardship and advocacy organizations in these watersheds.     

Water depth and lake-wide water level fluctuation influence on α- and β-diversity of coastal wetland fish communities

Coastal wetlands in the Laurentian Great Lakes are critical habitats for supporting fish diversity and abundance within the basin. Insight into the coupling of biodiversity patterns with habitat conditions may elucidate mechanisms shaping diverse communities. Within coastal wetlands, water depth as well as fluctuations in lake-wide water levels over inter-annual timescales, both have the potential to influence fish communities. Water level fluctuation can influence fish habitat structure (e.g., vegetation) in Great Lakes coastal wetlands, but it is unclear how water depth and lake-wide water level fluctuations affect fish community composition and diversity. Using β dissimilarity indices and multivariate ordination techniques, we assessed fish community structure among bulrush (Schoenoplectus acutus)-dominated wetlands in Saginaw Bay, Lake Huron, USA. We examined whether community structure was related to wetland water depth at the time of sampling and whether fish communities were more similar among years with similar Lake Huron water levels. Results suggested relatively high levels of both spatial (among wetlands) and temporal (among year) community dissimilarity that was driven primarily by species turnover. Thus, variability in water depths among wetlands and in Lake Huron water levels among years likely both contribute to regional fish diversity. Further, fish abundance and alpha diversity were positively correlated with wetland water depth at the time of sampling. Both climate change and anthropogenic water level stabilization may alter the magnitude and timing of water level fluctuations in the Great Lakes. Our data suggest that these changes could affect local fish community composition and regional fish diversity.     

When are Partnerships a Viable Tool for Development? Institutions and Partnerships for Water and Sanitation Service in Latin America

Partnerships are increasingly becoming unpopular in Latin America, they have narrowly been analysed in the context of the international political agenda and criticized for bringing benefits only to the private sector and not to the public sector and society at large. Nevertheless, there are successful experiences for providing water and sanitation at local level. The questions are: Are local level successful experiences the product of a partnership? Was it necessary to build partnerships to add value to the community presence and informal actors? What are the advantages of partnerships at local and national scale? The case studies presented demonstrate that actors need to have an incentive to work together and to build trust. The context in which they operate is also relevant, and in Latin America it is needed a strong national legal institutional framework if partnerships or any agreement should be an alternative to public delivery of water and sanitation. This paper analyses the context in which water and sanitation is delivered in peri-urban areas based on case studies, identified actions for effective provision and on discussion of the institutional framework options and partnership implementation at local and national level. This paper does not advocate partnerships per se; nor are these seen as the problem.     

Water Quantity and Quality in the Zerafshan River Basin: Only an Upstream Riparian Problem?

In discussing the 1997 UN Watercourses Convention, McCaffrey (1998) gave a theoretical example of the late-developer problem. This paper complements that theoretical example with a real case study of the Zerafshan basin in Central Asia. While McCaffrey addressed the water quantity issue in his example, the focus here also includes water pollution. The aim of the paper is to analyze some of the provisions of the mechanisms in the field of international water law—the Helsinki Rules and the UN Watercourses Convention—for water quantity and quality aspects, as well as to provide an insight into the basin regarding these two aspects.     

Water quality-based assessment of urban drainage impacts in Europe - where do we stand today?

Traditionally, design and optimisation of urban drainage systems was mainly driven by cost efficiency, surface flood prevention, and later by emission reduction. More recent procedures explicitly include ecological conditions of the receiving water in the definition of acceptable pollutant discharges via sewer system and treatment plant outlets. An ambient Water Quality based impact Assessment (WQA) principle therefore requires an integrative system optimisation. However, a broad range of mostly national WQA protocols exist across Europe varying in structure and complexity, assessment concept, spatial and temporal scope and handling of uncertainty. This variety inherently implies a considerable risk of subjectivity in the impact assessment with highly variable outcomes. The present review identifies differences and similarities of WQA protocols in use and discusses their strengths and weaknesses through: (i) a systematic comparison of WQA protocols by selected attributes, (ii) a review of real-life cases reported in the literature and expert interviews, and (iii) an illustration of our main findings by applying selected WQA in an instructive example. The review discusses differences in structure and concept, which are mainly identified for simplistic WQA protocols. The application of selected protocols to an example case shows a wide variety of numerical results and conclusive decisions. It is found that existing protocols target different questions within the decision making process, which users should be more aware of. Generally, to make assessments more reliable, further fundamental research is required to fully understand the relationship between stressors and stream ecosystem responses which will make assessments more reliable. Technically, tools suggested in WQA protocols show severe deficiencies and an uncertainty assessment should be mandatory.     

Priorities and Preferences in Water Quality Management - a Case Study of the Alsterån River Basin

Sweden is a decentralised country where local managers, who are key actors in water management, often deal with relatively difficult prioritisations, tradeoffs and conflicting goals. Many of these challenges relate to the effective implementation of the European Union Water Framework Directive. As an input to these challenges, the present paper elicits and analyses local and semi-local citizens’ preferences for water quality attributes related to the European Water Framework directive in a river basin located in southeast of Sweden. Based on a choice experiment tailored to the case study area, the paper analyses preferences for selected attributes based on real criteria for ecological water status in the implementation of the directive. The target population lives in the municipalities through which the river passes, or in municipalities neighbouring those. Despite this spatial proximity to the river, the analysis reveals limited knowledge and interest in matters related to the environmental quality of the river. There is no evidence that preferences differ between respondents with regard to experience or knowledge about the water basin, nor with regard to recreational habits in the area. These results offer input to local water management by providing information about preferences for explicit water quality attributes.

     

Direct Management or Inter-Municipal Cooperation in Smaller Municipalities? Exploring Cost Efficiency and Installed Capacity in Drinking Water Supply

Water Resources Management - The aim of this study is to determine whether, in small municipalities, drinking water services are supplied more efficiently under direct public provision or through...