Working towards sustainable urban water management: the vulnerability blind spot

The unprecedented water scarcity in Australia coincides with the adoption of a new urban water rhetoric. The 'Security through Diversity' strategy has been adopted in a number of Australian cities as a new and innovative approach to urban water management. Although this strategy offers a more holistic approach to urban water management, in practice, the Security through Diversity strategy is largely being interpreted and implemented in a way that maintains the historical dependence on large scale, centralised water infrastructure and therefore perpetuates existing urban water vulnerabilities. This research explores the implementation of Security through Diversity as the new water scarcity response strategy in the cities of Perth and Melbourne. Through a qualitative study with over sixty-five urban water practitioners, the results reveal that the practitioners have absorbed the new Security through Diversity language whilst maintaining the existing problem and solution framework for urban water management. This can be explained in terms of an entrenched technological path dependency and cognitive lock-in that is preventing practitioners from more comprehensively engaging with the complexities of the Security through Diversity strategy, which is ultimately perpetuating the existing vulnerability of our cities. This paper suggests that greater engagement with the underlying purpose of the security though diversity strategy is a necessary first step to overcome the constraints of the traditional technological paradigm and more effectively reduce the continued vulnerability of Australian cities.     

Urban Water Management in Developing Arid Countries

Urbanization, industrialization and rapid population growth in developing countries of the Arabian Peninsula are putting increasing pressure on local water authorities and water planners to satisfy the growing urban water and sanitation demands. In the Arabian Peninsula, water resources are limited, average rainfall is low and the seawater and brackish water desalination in addition to limited groundwater resources are the major water supply sources. The population increased from about 17.688 million in 1970 to 38.52 million in 1995 and is expected to reach 81.25 million in 2025. The urban population is expected to rise from 60% in 1995 to more than 80% in 2025. The domestic water demand is expected to rise from 2863 million cubic metres (MCM) in 1990 to about 4264 MCM in 2000 and 10580 MCM in 2025. In Saudi Arabia, the population increased by 143.6% between 1970 and 1995; and it is expected to reach about 40.426 million in 2025, with about 80% urban population. The domestic water demand in the Kingdom is expected to be about 2350 MCM in 2000 and 6450 MCM in 2025. Specialized agencies have been established for water production and distribution, and for wastewater collection, treatment and reuse. Special legislation has been introduced to manage water demands and to protect the interests of the community and its natural resources. Fifty-seven costly desalination plants have been constructed in the Peninsula on the Gulf and Red Sea coasts, as well as water transmission lines to transport the desalinated water to coastal and inland major cities. The seawater desalination unit cost is about US$0.70/m 3 for a large desalination plant with energy priced at world prices. More than $30 billion has been invested on water and sanitation projects. Present desalination production is about 46% of the total domestic demand, and the rest is pumped from deep and shallow aquifers. In general, fragmented legislation and institutional arrangements and low water charges have indirectly resulted in over-usage of domestic water, production of excessive quantities of wastewater, significant leakage, and enhancement of shallow water-table formation and rise in some cities. Facing the challenges of satisfying the growing urban water demands requires several essential measures such as: (a) introduction of new technologies to reduce water demands, and losses, and to enhance wastewater recycling and water conservation; (b) the updating of legislation to coordinate both responsibilities and actions among different water agencies; (c) the introduction of a strong and transparent regulatory framework to adopt different forms of water supply privatization, to reduce the costs of building, operation and maintenance of water and sanitation facilities, and to improve the level of services and billing, leakage and wastewater collection and treatment; (d) an increase in water tariffs to reflect the actual value of the water, and to enhance the awareness of public as to the value of water; and (e) development of short-term and long-term national water plans based on realistic water demand forecasting.     

Modeling Multisource Multiuser Water Resources Allocation

Water shortage emerges and restricts the urban construction and the socio-economy development due to the rapid expansion of the cities throughout the world. Recently treated wastewater reuse, including rainwater collection and utilization, and seawater desalination, etc., has been put in practice in some cities. This paper presents the characteristics of urban multisource water and multiuser and a multi-objective optimization model of reasonable allocation on multisource water for multiuser under sufficiently considering the harmonious development among economy, society and environment. As a case study this model had been applied to the reasonable allocation of water supply and demand in Dalian City in 2010, 2015 and 2020, in which the maximal benefit of economy, society and environment was regarded as the multi-objectives and the step method was adopted to solve the model. The result indicates that the proportion of the reused water to the total water consumption is gradually increasing, but the proportion of the high quality water to the total water consumption is decreasing. In other words, as a secondary water resource, the reused water has replaced partial high quality water gradually. Consequently, the reasonable allocation of urban multisource water for multiuser is the available approach to alleviate urban water crisis and achieve the sustainable utilization of urban water resources.     

Economic Analysis of Environmental Issues Regarding Seawater Desalination

Abstract

Desalination of seawater is becoming an important source of drinking water in many cities and towns, where the demand for water continues to increase, while the supply of fresh water is limited. We examine the economic aspects of several environmental issues that arise during consideration of desalination projects. We present a conceptual framework that demonstrates the differences between public and private objectives, and we use that framework to describe policies that can encourage firms and consumers to consider environmental impacts. Public policies can be implemented also to stimulate technological developments that will reduce the environmental impacts of desalination. We also examine the potential growth inducement effects of seawater desalination by describing the likely impacts of desalination on both the demand and supply components of the market for municipal water in a coastal area.     

The application of economic-engineering optimisation for water management in Ensenada, Baja California, Mexico.

Mathematical optimisation is used to integrate and economically evaluate wastewater reuse, desalination and other water management options for water supply in Ensenada, Baja California Mexico with future levels of population and water demand. The optimisation model (CALVIN) is used to explore and integrate water management alternatives such as water markets, reuse and seawater desalination, within physical capacity constraints and the region's water availability, minimising the sum of economic costs of water scarcity and operating costs within a region. The modelling approach integrates economic inputs from agricultural and urban water demand models with infrastructure and hydrological information, to identify an economically optimal water allocation between water users in Ensenada. Estimates of agricultural and urban economic water demands for year 2020 were used. The optimisation results indicate that wastewater reclamation and reuse for the city of Ensenada is the most economically promising alternative option to meet future water needs and make water imports less attractive. Seawater desalination and other options are not economically viable alone, but may have some utility if combined with other options for the Ensenada region.     

Water access in Sucre,Bolivia: a case of governance deficit

Bolivia is one of the countries on the American continent with the lowest rates of access to water, a situation that has caused confrontation between civil society and water utility managers in some cities. This research describes the water access scenario in Sucre, the capital of Bolivia, together with the key challenges faced by the company that manages the water services in the city. The case of Sucre is an example of how poor water governance can generate inefficiencies in the management of the service. Taking this into consideration, policy and institutional reforms are recommended to facilitate decision making aimed at improving the current situation of access to water.     

Practitioner Perceptions of Social and Institutional Barriers to Advancing a Diverse Water Source Approach in Australia

Traditional urban water management systems are ill-equipped to address future challenges. Despite policy rhetoric supporting Total Water Cycle Management and the diverse water supply approach, there are many social and institutional barriers to effective implementation. A quantitative online survey with over 1000 practitioners in three Australian capital cities identified practitioners' level of receptivity to the diverse water source approach, and their experience of the scope and priority of such barriers to their implementation. The analysis revealed a high level of practitioner support, yet a critical lack of institutional tools and incentives for supporting implementation. The paper provides a series of recommendations for addressing this issue.     

A Decision Support System to Manage the Groundwater of the Zeuss Koutine Aquifer Using the WEAP-MODFLOW Framework

This paper describes the development of a Decision Support System (DSS) for groundwater management of the ‘Zeuss Koutine’ aquifer in southeastern Tunisia using the WEAP-MODFLOW framework. First, a monthly MODFLOW model was developed to simulate the behaviour of the studied aquifer. A conceptual model of the study area was designed and a WEAP schematic representing the real hydraulic system was developed. In addition to the studied aquifer, other water resources available in the region, such as desalination plants and groundwater, were taken into consideration in this DSS. Inputs to the hydrogeological model include natural recharge and inflow from higher neighbouring aquifers. Outputs are mainly agricultural, touristic and urban water consumption. It was shown that the DSS developed was able to evaluate water management scenarios up to 2030, especially future water consumption, transmission link flow and active cell heads of the MODFLOW model for each time step. Results for the Zeuss Koutine aquifer demonstrated that desalination plants already built in the cities of Jerba and Zarzis have contributed to decreasing the continuous drawdown observed before 1999. The use of a sea water desalination plant to supply Jerba and Zarzis in the future is a solution for reducing the Zeuss Koutine aquifer drawdown. Defining its optimal capacity over time poses a new research question.     

泉州市城镇居民综合生活需水预测方法研究

本文采用定额法、趋势分析法、年均增长率法、回归分析法等需水预测常用的方法,对泉州市城镇居民综合生活用水进行预测分析,经多种预测结果比较得出泉州市2030年城镇居民综合生活需水量为8.62亿m 3。其中定额法、回归分析法预测结果较好,趋势分析法和年均增长率法更常用于经济社会发展指标的预测。随着中国城镇化水平不断推进,居民综合生活用水量的影响愈加多元化、横向化,建立多元回归预测分析模型来预测用水量是很好的选择,该研究可为其他城市预测规划水平年居民生活用水量提供借鉴。     

Conjunctive use of Inter-Basin Transferred and Desalinated Water in a Multi-Source Water Supply System Based on Cost-Benefit Analysis

Water shortage has forced coastal cities to seek multi-source water supply with a focus on inter-basin water and desalinated seawater. The differences of water supply costs pose a challenge in the optimal use of multiple water resources. This paper aims to understand the impact of desalinated seawater’s variable costs on multi-source water supply through a cost-benefit analysis method based on a multi-objective optimization model, considering different combination scenarios of desalination yield, streamflow condition, seawater desalting plant (SDP) scheme, water shortage index and utilization ratio of the SDP. The application in the coastal city Tianjin, China shows that the desalination yield has an impact on the tradeoff between the water shortage index and the total water supply cost and an optimal desalination yield can be determined at a turning point. And where the turning point appears is influenced by the utilization ratio of the SDP and streamflow conditions of inter-basin water. Moreover, a single centralized SDP is found to have an overall lower water supply cost than several decentralized small-sized SDPs. Lower water shortage index leads to higher cost, and the unit decrease of shortage index will need more added cost when the shortage index is very low. This method is proven to be effective in identifying the best conjunctive use of inter-basin water and desalinated seawater, which can contribute to relieve urban water shortage.     

Developing Novel Approaches to Tracking Domestic Water Demand Under Uncertainty—A Reflection on the “Up Scaling” of Social Science Approaches in the United Kingdom

Climate change, socio-demographic change and changing patterns of ordinary consumption are creating new and unpredictable pressures on urban water resources in the UK. While demand management is currently offered as a first option for managing supply/demand deficit, the uncertainties around demand and its’ potential trajectories are problematic for water resources research, planning and policy. In this article we review the ways in which particular branches of social science come together to offer a model of ‘distributed demand’ that helps explain these current and future uncertainties. We also identify potential strategies for tracking where the drivers of change for demand may lie. Rather than suggest an alternative ‘demand forecasting’ technique, we propose methodological approaches that ‘stretch out’ and ‘scale up’ proxy measures of demand to inform water resources planning and policy. These proxy measurements could act as ‘indictors of change’ to water demand at a population level that could then be used to inform research and policy strategies. We conclude by arguing for the need to recognise the co-production of demand futures and supply trajectories.     

Groundwater Rise Problem and Risk Evaluation in Major Cities of Arid Lands – Jedddah Case in Kingdom of Saudi Arabia

Arid lands are in the need of additional water supply but water transportation from outside of the natural hydrological cycle causes the groundwater to rise within the urban areas. Additional water supply from surrounding areas or through the desalination plants provides comfort in domestic activities but after the usage, its disposition is necessary in an efficient manner. Unfortunately, arid region cities have neither sufficient nor efficient sewage system. Consequently, the water returned to surface cesspools and leakages from insufficient sewage system makes internal groundwater recharge within the urban area. Additionally, water supply system leakages further raise the groundwater level. Deterioration in water quality becomes a potential danger for the infrastructure and foundations. Surface depressions in the city may be flooded due to groundwater level rise and at times bed smells occur at various parts of the city. In this paper, a quantitative method is followed to assess groundwater level rise risks in addition to the few chemical risks associated with sulfate and chloride solids. It is observed that each one of these variables has different probability distribution function and expose risk maps with different features.     

Sustainable sanitation and water in small urban centres.

The objective of this paper is to review the global trends in urbanization with respect to availability of adequate sanitation and water supply services. Urbanization is unrelenting and rapid increase in the urban population in the less developed countries is of major global concern regarding this topic of sustainable sanitation and water. Most global urban growth is in the smaller cities and in the developing world. Half the urban developing world lacks adequate water and sanitation. Global urban access to waterborne sanitation is not affordable and thus is not a realistic option so alternative approaches are necessary. The treatment of drinking water cannot be a substitute for sanitation. In order to achieve sustainable sanitation, a change in attitude about human excreta and use of water is required. Essential features of a sustainable sanitation system are: containment, sanitisation and recycling. To improve water supply, we need to improve management practices, use full-cost pricing, introduce watershed approaches to protection and provide improved sanitation. Small urban initiatives need to go beyond the traditional sectors and new initiatives are required like on-site urban ecostations, source-separation of urine and faeces, decentralised greywater treatment and integration of sanitation into the cost of housing.     

Sustaining Urban Water Supplies in India: Increasing Role of Large Reservoirs

Urban water demand is rapidly growing in India due to high growth in urban population and rapid industrialization. Meeting this demand is a big challenge for the urban planners in India. Incidentally, the large urban areas are experiencing faster growth in population, and most of them are in arid and semi arid regions, which are naturally water-scarce. As a result, water supplies from local water resources including aquifers are falling far short of the high and concentrated demands in most urban areas. Under such situations, these large cities have to rely on distant large reservoirs. The analysis of 302 urban centers shows that cities with larger population size have much higher level of dependence on surface water sources. Also, greater the share of surface water in the city water supplies, higher was the level of per capita water supply. Multiple regression models are estimated for Class I cities and Class II towns in India. The results show that Population Elasticity of Water Supply (PEWS) change with time and space—for Class I cities it was 1.127 in 1988, whereas that with respect to 1999 population is 1.289. It also shows that Class I cities have better water supply (PEWS is 1.127 in 1988 and 1.289 in 1999) than Class II towns (PEWS is 0.396 in 1988 and 0.675 in 1999). Given the structure and pattern of urban population growth, economic conditions and water demands, large reservoirs will have a much bigger role in meeting urban water supply needs.     

Sustainable Urban Water System Transitions Through Management Reforms in Ghana

Despite decades of water reforms, Ghana’s struggle to achieve sustainable urban water system is deepened by complex interactions of multi-layered political, socio-economic and managerial characteristics, leaving a rationing system of water supply in major cities like Accra. Using a multi-level perspective framework, the paper examines the dynamics of urban water system transition through management reforms. The study showed how external pressure at the landscape level influenced policy direction within urban water regime through the implementation of neo-liberal economic policies, paving way for resistance and grassroots innovation at the niche level. The implementation of such policies in the reform process did little to help achieve the desired sustainable urban water system goals. The paper suggests a blend of public and private financing with support for grassroots to improve urban water system management. However, subsequent urban water policy reforms must be informed by knowledge of social, economic, and political realities rather than imported generic “best policies and practices” that often conflict with local realities.     

The Role of Desalination in Meeting Water Supply Demands in Western Asia

Abstract

The increasing gap between the supply and demand for water in the Economic and Social Commission of Western Asia (ESCWA) member countries: Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Oman, Palestine, Qatar, Saudi Arabia, United Arab Emirates, and Yemen) can be attributed to the limited availability of surface water, mining of fossil groundwater sources, and water pollution mainly of shallow aquifers, deficient institutional structure, poor management processes, and inapt allocation of financial resources. The non-sustainable use of natural water resources to meet the escalating water demand has also contributed to the depletion and deterioration of water quality and quantity. To meet water supply shortages in the domestic sector, water desalination has been entrenched as a viable option for the Gulf Cooperation Council (GCC), which includes the following countries: Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates. The objective of the paper is to investigate the role of water desalination in meeting the water demands in the ESCWA member countries. The significant role of desalination is highlighted with emphasis in evaluating not only its production trends, processes, and costs, but also its capacity in the provision of water demands. Water desalination has become a major and staunch water source for a number of large urban centers. For such countries such as Bahrain, Kuwait, and Qatar and the coastal zone areas of Oman, United Arab Emirates (UAE), and Saudi Arabia, desalination represents one of the most feasible and strategic alternative options for their current and future domestic water supply requirement. Given the high consumption rate from this source and its high production cost, fundamental efforts must be integrated and invested in both research and development programs to implement comprehensive conservation measures that would lead to a reduction in the consumption rates. Parallel to these achievements, efforts should be directed within the context of integrated management of water resources, to identify alternative potential water resources, to meet future water challenges.     

基于PEST模型的海岛海水淡化产业环境分析

海水淡化是解决海岛淡水短缺的重要途径之一。为推广海水淡化在海岛的应用,在对海岛特点和海水淡化工程分析总结的基础上,结合PEST模型,从政治政策、经济、社会、技术4个方面系统分析了海水淡化产业在海岛发展的外部环境;运用SWOT-PEST矩阵全面分析这4个方面的优势和劣势、机遇和挑战,探讨海岛海水淡化产业发展现状及前景。并从国家政策、市场经济、公众接受、技术创新等方面提出战略对策建议和保障措施,为海岛海水淡化产业的发展提供依据。     

Using Policy and Regulatory Frameworks to Facilitate Water Transitions

There are persistent calls across policy, industry and academia for urban water transitions in order to deliver increased sustainability, liveability and resilience. However, realisation of such transformational change is difficult, and there are a number of undesirable or unsuccessful transition trajectories that can manifest. Drawing on a contemporary stormwater quality management transition in South-East Queensland, Australia, this qualitative research paper provides an empirical exploration of a transition in struggle. The paper examines why and how this transition trajectory unfolded, focusing specifically on the evolution of culture, structure and practice changes from the 1970s to the present-day. The paper makes two scholarly contributions, firstly confirming the dynamic nature of transformational change and indicating the need to design transition initiatives across the culture, structure and practice domains to co-evolve and thereby build a robust and mutually reinforcing transition foundation. The results also reveal the critical role of regulation in providing a safety net for the transition and enabling continued progress even when commitment to policy goals wavers. These results also provide practical insight for practitioners engaged in the implementation of transition processes, and reveal the need for transition advocates to deliberately and proactively engage with regulatory frameworks to embed a novel practice.     

西安市工业需水量预测及污水回用于工业研究

随着城市化与工业化水平的不断提高，水资源短缺问题日益突出，工业需水量的合理预测已成为城市供水和水资源规划极其重要的部分，以西安市为研究对象，对其主要工业需水量采用灰色预测理论进行了预测研究。根据灰色预测理论预测结果确定西安市未来年份的工业需水量，依托西安市第四轮城市总体规划建成的15个污水厂，通过城市污水回用来解决西安市未来工业需水量需求。     

Chilean Water Policy: The Role of Water Rights,Institutions and Markets

Allocation of water through markets in tradable water rights in Chile has fostered efficient use of water; facilitated a shift to high-value crops which use less water per unit value of output; has given farmers greater flexibility to shift cropping patterns according to market demand through the purchase, rent and lease of water; and induced im proved efficiency in urban water and sewage services. In addition, the Chilean water policy, by reducing huge con struction and operations and maintenance subsidies to better-off farmers and urban water consumers, has freed-up public resources that have been utilized to provide direct and transparent targeted subsidies for poor urban water users and small farmers. This paper discusses the political and economic environment that facilitated the establishment of the new water policy, and describes the characteristics of tradable water rights in Chile and the legal and institutional basis for enforcing them.