Governing Non-Potable Water-Reuse to Alleviate Water Stress : The Case of Sabadell , Spain

The world will experience an estimated 40% freshwater supply shortage by 2030, converting water scarcity into one of the principal global challenges that modern society faces. Urban water reuse is recognized as a promising and necessary measure to alleviate the growing water stress in many regions. The transformation to widespread application of water-reuse systems requires major changes in the way water is governed, and countries such as Spain already find themselves involved in this process. Through the systematic assessment of the city of Sabadell (Spain), we aim to identify the main barriers, opportunities and transferable lessons that can enhance governance capacity to implement systems for non-potable reuse of treated wastewater in cities. It was found that continuous learning, the availability and quality of information, the level of knowledge, and strong agents of change are the main capacity-building priorities. On the other hand, awareness, multilevel network potential and implementing capacity are already well-established. It is concluded that in order to undertake a widespread application of water-reuse practices, criteria examining water quality according to its use need to be developed independently of the water’s origin. The development and implementation of such a legislative frame should be based on the experience of local water-reuse practices and continuous evaluation. Finally, the need for public engagement and adequate pricing mechanisms are emphasized.


Introduction
Approximately four billion people experience severe water scarcity during at least one month per year, while over 500 million people face severe water scarcity, with water consumption exceeding the renewable resource by a factor of two or more [1].The agricultural sector is responsible for 70% of the world's water consumption whereas industry and municipalities withdraw 19% and 11%, respectively.However, Hoekstra et al. estimates that agriculture accounts for up to 92% of the global urban water footprint [2].Large increases in freshwater demand can be expected in the next decade, particularly for industrial production in urban areas [3].These developments are estimated to lead to a 50% increase in water demand in developing countries by 2025 [4] and a 40% freshwater supply shortage worldwide by 2030 [5].A wide plethora of factors including population growth, diets shifting towards water-intensive foods such as meat, groundwater depletion, salinization caused by unsustainable irrigation, as well as saltwater intrusion and sea level rise, which further increase the pressure on freshwater resources [1][2][3][4][5][6][7].The impact of water scarcity is expected to lead to substantial unemployment.In particular, water-dependent labor in arid and semi-arid areas-95% of which are agricultural jobs-will be affected.This type of unemployment may lead to food insecurity and social instability that could trigger large scale involuntary migration towards cities and across continents [8].These risks urge for water-use efficiency and water-reuse.
Wastewater is increasingly being considered, a largely untapped resource for freshwater and raw materials that can alleviate water stress [7].At present, high-income countries treat 70% of their wastewater, upper-middle-income countries 38% and lower-middle-income countries 28%.Only 8% of the wastewater in low-income countries undergoes any kind of treatment [9].Altogether, this means that an estimated 80% of the wastewater is released into the environment untreated [6] which leads to eutrophication, biodiversity loss and can threaten drinking water, fisheries, aquaculture and tourism [10].Reusing treated wastewater therefore has a large potential to alleviate water stress.Moreover, since 80% of all wastewater is not treated, many Waste Water Treatment (WWT) systems have yet to be built.Thus, WWT systems and reuse systems may be a promising solution package to improve public health, reduce water pollution and alleviate water scarcity in particular in water-scarce urban regions.
The European Commission has recognized the untapped potential of treated wastewater, and has called for "closing the loop" through a circular economy approach [11].It recognizes and enables the reuse of wastewater as a safe solution to reduce water demand.From the total reused tertiary treated water only 2.3% is for potable purposes whereas most water is reused for irrigation (52%), industry (19.3%) and non-potable urban applications (8.3%) [12].
In order to reduce water stress by a wider application of wastewater-reuse practices in cities, major changes are required in the way the water cycle is governed at the local, regional and national level.Spain is in the middle of such a transformation process where various multi-level governance barriers and challenges emerge [13].Despite the fact that a number of water reuse applications have already been developed and established in many countries, the widespread adoption or 'mainstreaming' of water reuse practices appears to be slow and various technical and non-technical barriers have been published [14][15][16][17].In environmental governance literature, a plethora of social factors and conditions have been identified that impede or enhance climate adaptation such as water reuse schemes [18][19][20].However, most identified conditions are based on conceptual and theoretical considerations with a lack of emphasis on empirical validation [18,21,22].In addition, concepts and definitions are often inconsistent, non-specific and in part, overlap each other [19,20].If findings are not organized in a common framework, isolated knowledge will not cumulate [23].Hence, a diagnostic framework is required that facilitates the accumulation of coherent knowledge that could improve the understanding of the barriers, opportunities and lessons beyond the case study itself [19].Water scarcity issues transcend administrative boundaries and involve many stakeholders.The capacity to collaborate, to collectively overcome different barriers, is therefore essential.A promising way to consistently analyze the main barriers and opportunities that might emerge in the adoption of water reuse schemes is through the concept of governance capacity.There are multiple definitions of governance capacity.However, a few common traits can be defined [24].First, capacity refers to the ability of actors to jointly act in the face of collective challenges.Second, capacity is the product of actors' interaction that is influenced by the socio-institutional setting.Third, actors' values, culture and interests shape their interactions and influence collective problem-solving.Accordingly, we apply the definition of Koop et al. who defined governance capacity as 'a set of key governance conditions that should be developed to enable change that will be effective in finding dynamic solutions for water challenges in cities' [24].
In this paper, we focus on the governance capacity of cities to alleviate water stress by applying wastewater-reuse for non-potable purposes.Through a case study in the city of Sabadell (Spain), this paper aims to identify the main barriers, opportunities and transferable lessons that can enhance the governance capacity to implement systems for non-potable reuse of treated wastewater in cities.
This paper has the following structure.Section 2 describes the applied methodology and Section 3 provides the results of the case study.Section 4 provides a discussion of the results and reflects on possible transferable lessons from Sabadell for other cities in Spain, the Mediterranean and other water-stressed regions.The main conclusions are provided in Section 5.

Methodology
Based on an extensive literature review, Koop et al. [24] developed a diagnostic framework in order to assess the most important conditions that together determine the capacity to govern water challenges.The Water Governance Capacity Framework (GCF) consists of three dimensions, nine conditions and 27 indicators (Table 1).The "knowing" dimension relates to the need to be aware, understand, and learn about the risks and impacts of policy and strategic choices.The "wanting" dimension refers to the need for actors to commit, cooperate, act upon ambitions and use their skills to find solutions.The "enabling" dimension refers to network, resources, and instruments that actors require to realize their ambitions.Each indicator has its own pre-defined question and indicator-specific 5-point Likert scale, ranging from very encouraging (++) to very limiting (−−) of the overall governance capacity to address a water challenge.A detailed description of each indicator's pre-defined question is provided in Table 2.For the indicator-specific Likert scale and link to the literature, we refer to reference [25].By substantiating the scores of each indicator according to a triangular approach, the findings are validated in a standardized and reproducible way.This triangular approach consists of three steps: 1.
A desk study of scientific literature, official government sources, policy documents and grey literature resulting in a report of the substantiated preliminary Likert score of each indicator.

2.
The construction of a standardized importance/influence matrix to identify stakeholders, categorize them, and specify their roles and responsibilities [26].In this matrix, importance refers to the priority given to satisfy the needs and interests of a stakeholder.Influence refers to the power of stakeholders to enhance or impede a policy, plan or objective.The importance/influence matrix consists of four classes: (1) crowd (low importance and low influence); (2) context (low importance and high influence); (3) subjects (high importance and low influence); and (4) key players (high importance and high influence).For each class, at least one stakeholder representing the government, the market and civil society were selected as suggested by Lange et al. [27].
A coding system is applied in this paper to refer to maintain anonymity, where [SR001], [SR002], [SR003] and so on refer to the conducted interviews.The interviews were conducted face-to-face, lasted approximately 1 hour each and were recorded to increase the accuracy of the information gathered.

3.
All interviewees were asked for their reactions to the indicator scores and their respective explanations.Their feedback took the form of additional information and they were asked to support their statements with reports, policy references, arguments etc.Based on the incorporation of the aforementioned further input, the final indicator scores were determined.
The selected stakeholders represented the organizations Simbiosy, the General Water Society of Barcelona (SGAB), the Consortium of Integrated Water Management of Catalunya (CONGIAC), Sabadell's wastewater treatment plant, Riusec (EDAR RIUSEC), the University of Barcelona, the Polytechnic University of Catalonia, the local water service utility, Aigues Sabadell (CASSA), the Institute of Environmental Assessment and Water Research (IDAEA), the Technical Service Consortium of the Costa Brava, Figueres City Council, Sabadell City council, Barcelona Provincial Government and the Catalan Water Agency.Experts from the identified key stakeholders were selected for semi-structured interviews in order to gather the information to score the indicators and also to receive follow-up questions for clarification or to better understand the content.People with different roles, expertise and responsibilities were selected to reduce the risk of bias and in order to unravel socially desirable responses.A coding system is applied in this paper to consistently refer to these anonymized interviews.The overall indicator scores were determined based on the separate interview scores and the collection of additional information that may ratify or provide nuance to the interview findings.Altogether, 16 interviews were conducted during the period, 6 June-6 July, 2017.
Table 2. Overview of pre-defined questions to be answered by the researcher based on a triangular approach consisting of three steps: (1) literature review; (2) in-depth interviews with selected experts; (3) feedback procedure.The full details of the Likert scoring are provided on the EIP Water website [25].

Indicator
Pre-Defined Question

community knowledge
To what extent is knowledge regarding the current and future risks, impacts, and uncertainties of the water challenge dispersed throughout the community and local stakeholders who may result in their involvement in decision-making and implementation?

Local sense of urgency
To what extent do actors have a sense of urgency, resulting in widely supported awareness, actions, and policies that address the water challenge?

Behavioural internalization
To what extent do local communities and stakeholders try to understand, react, anticipate and change their behaviour in order to contribute to solutions regarding the water challenge?

Information availability
To what extent is information on the water challenge available, reliable, and based on multiple sources and methods, in order to meet current and future demands so as to reveal information gaps and enhance well-informed decision-making?

Information transparency
To what extent is information on the water challenge accessible and understandable for experts and non-experts, including decision-makers?

Knowledge cohesion
To what extent is information cohesive in terms of using, producing and sharing different kinds of information, usage of different methods and integration of short-term targets and long-term goals amongst different policy fields and stakeholders in order to deal with the water challenge?

Smart monitoring
To what extent is the monitoring of process, progress, and policies able to improve the level of learning (i.e., to enable rapid recognition of alarming situations, identification or clarification of underlying trends)?Or can it even have predictive value?

Evaluation
To what extent are current policy and implementation continuously assessed and improved, based on the quality of evaluation methods, the frequency of their application, and the level of learning?

Cross-stakeholder learning
To what extent are stakeholders open to and have the opportunity to interact with other stakeholders and deliberately choose to learn from each other?

Stakeholder inclusiveness
To what extent are stakeholders interacting in the decision-making process (i.e., are they merely informed, are they consulted or are they actively involved)?Are their engagement processes clear and transparent?Are stakeholders able to speak on behalf of a group and decide on that group's behalf?

Protection of core values
To what extent ( 1) is commitment focused on the process instead of on early end-results?
(2) do stakeholders have the opportunity to be actively involved?(3) are the exit procedures clear and transparent?(All three ensure that stakeholders feel confident that their core values will not be harmed.)

Progress and variety of options
To what extent are procedures clear and realistic, are a variety of alternatives co-created and thereafter selected from, and are decisions made at the end of the process in order to secure continued prospect of gain and thereby cooperative behaviour and progress in the engagement process?

Ambitious and realistic management
To what extent are goals ambitious (i.e., identification of challenges, period of action considered, and comprehensiveness of strategy) and yet realistic (i.e., cohesion of long-term goals and supporting flexible intermittent targets, and the inclusion of uncertainty in policy)?

Discourse embedding
To what extent is sustainable policy interwoven in historical, cultural, normative and political context?

Management cohesion
To what extent is policy relevant for the water challenge, and coherent regarding (1) geographic and administrative boundaries; and (2) alignment across sectors, government levels, and technical and financial possibilities?

Entrepreneurial agents
To what extent are the entrepreneurial agents of change enabled to gain access to resources, seek and seize opportunities, and have an influence on decision-making?

Collaborative agents
To what extent are actors enabled to engage, build trust and collaborate, and connect business, government, and sectors, in order to address the water challenge in an unconventional and comprehensive way?

Visionary agents
To what extent are actors in the network able to manage and effectively push forward long-term and integrated strategies which are adequately supported by interim targets?

Room to manoeuvre
To what extent do actors have the freedom and opportunity to develop a variety of alternatives and approaches (this includes the possibility of forming ad hoc, fit-for-purpose partnerships that can adequately address existing or emerging issues regarding the water challenge)?

Clear division of responsibilities
To what extent are responsibilities clearly formulated and allocated, in order to effectively address the water challenge?

Authority
To what extent are legitimate forms of power and authority present that enable long-term, integrated and sustainable solutions for the water challenge?

Affordability
To what extent are water services and climate adaptation measures available and affordable for all citizens, including the poorest?

Consumer willingness to pay
How is expenditure regarding the water challenge perceived by all relevant stakeholders (i.e., is there trust that the money is well spent)?

Financial continuation
To what extent do financial arrangements secure long-term, robust policy implementation, continuation, and risk reduction?

Policy instruments
To what extent are policy instruments effectively used (and evaluated), in order to stimulate desired behaviour and discourage undesired activities and choices?

Statutory compliance
To what extent is legislation and compliance, well-coordinated, clear and transparent and do stakeholders respect agreements, objectives, and legislation?

Preparedness
To what extent is the city prepared (i.e., there is clear allocation of responsibilities, and clear policies and action plans) for both gradual and sudden uncertain changes and events?

Case Study Description
At present, around 11% of total treated wastewater is reused in Spain [11].Spain has experienced several episodes of water stress during the 1990s and the early 21st century.In particular, several acute droughts led to domestic water cuts and at times required the use of sea-going water tankers from different locations in the Mediterranean coast [13].In order to alleviate water stress, the central government and regional governments have promoted desalination plants and have devised a National Plan for Water-reuse [13].In particular, before 2011, approximately 50 municipalities in Catalunya had approved local regulations to promote decentralized reuse systems.The actions for the use of reclaimed water in Spain, mainly consist in transporting it for specific uses, such as the watering of golf courses and public gardens, the cleaning of streets, or for agriculture and industry.The implementation of a distribution network for reclaimed water, coexisting with the drinking water network, has, to date, been applied in only a few cities, such as Madrid and Sabadell.Only in Sabadell is water supplied for the use of flushing toilets.
With a population of over 208,000 people, Sabadell is the co-capital and second largest city of the County of Valles Occidental in Catalonia, Spain [28].It is situated 22 km north of Barcelona, in the basins of the rivers Ripoll and Riusec, both integrated within the Besos River Basin.It is a highly commercial and industrial city that acts as a driving force for economic and urban development.A dual network is already applied in a large part of the city that separately distributes drinking water and treated non-potable water from the EDAR Riusec treatment plant and from groundwater sources.The second WWT plant of the city, Riu Ripoll, returns treated wastewater upstream of the Ripoll River, aiming to restore the ecological flow.Together these plants treated 22,544 m 3 day −1 and 14,170 m 3 day −1 respectively in 2017 [29].Nonetheless, the total amount of treated non-potable water supplied through the dual network is only around 274 m 3 day −1 .
The governance of the water sector in Sabadell is composed of both private and public stakeholders.In Spain, the national and regional governments mandate the normative and legislative contexts.Nonetheless, each municipality is responsible for the management of the water in its jurisdiction.Thus this role falls in the hands of the City council of Sabadell.This municipality, among others, has subcontracted the private company CASSA to do this.In addition, Water of Sabadell (CASSA) has recently become part of AGBAR (Aguas Barcelona), which in turn is predominantly owned by Suez Environment.The stakeholders with high influence and the most interest were identified as the Catalan Water Agency (state), the Provincial Government of Barcelona (state), CASSA (market) and the City Council of Sabadell (state).The stakeholders with a high interest but low influence are EDAR Water Treatment plant (state/market), Network of Cities & Towns for Sustainability (Civil Society), Consortium of Besos Tordera and the Catalan Association of Friends of Water (Civil Society).
A desk study of Sabadell's Integrated Water Resources Management (IWRM)-called a City Blueprint-was performed within the European POWER project (https://www.power-h2020.eu/)and indicated that the city is vulnerable to heat risk and water scarcity (Figure 1 [30]).In addition, financial pressures such as high unemployment (18.4%) and a moderate average GDP per capita (25,684 USD/year) could affect urban water management investments.Sabadell has a high drinking water quality, with 187/187 samples that meet the quality standards [29].Furthermore, Sabadell's drinking water consumption of 96 L per person per day is one of the lowest rates in Europe of domestic water consumption.The average age of the pipes of the drinking water distribution network is 38 years, so some areas require refurbishment.Non-revenue water accounts for 19.4%.

Results
The results of the Governance Capacity Framework on site research show that the multi-level governance system of Sabadell is complex and that the reuse of treated wastewater for non-potable purposes is progressive, but not yet widely adopted in the centralized water governance system in the area of Catalonia.Figure 2 summarizes the results of Sabadell's multi-level governance capacity to alleviate water stress by wastewater-reuse schemes.The indicators are ranked from most limiting to most encouraging concerning the capacity to govern practices of water reuse.The limiting and encouraging conditions are presented systematically in accordance with Table 1.

Condition 1: Awareness
The level of knowledge about the region's water scarcity and the amplifying impact of climate change are found to be relatively high [SR015].However, there is little understanding with regards to how the water is used and distributed within the region, the linkages and interdependencies in relation to weather patterns, land use or environmental processes (indicator 1.1).Accordingly, the impacts on the water quality of rivers, groundwater, and the risks and uncertainties associated with the increasing water scarcity are largely underestimated

Results
The results of the Governance Capacity Framework on site research show that the multi-level governance system of Sabadell is complex and that the reuse of treated wastewater for non-potable purposes is progressive, but not yet widely adopted in the centralized water governance system in the area of Catalonia.Figure 2 summarizes the results of Sabadell's multi-level governance capacity to alleviate water stress by wastewater-reuse schemes.The indicators are ranked from most limiting to most encouraging concerning the capacity to govern practices of water reuse.The limiting and encouraging conditions are presented systematically in accordance with Table 1.

Condition 1: Awareness
The level of knowledge about the region's water scarcity and the amplifying impact of climate change are found to be relatively high [SR015].However, there is little understanding with regards to how the water is used and distributed within the region, the linkages and interdependencies in relation to weather patterns, land use or environmental processes (indicator 1.1).Accordingly, the impacts on the water quality of rivers, groundwater, and the risks and uncertainties associated with the increasing water scarcity are largely underestimated [SR002-SR011-SR013-SR015-SR016].The general sense of urgency of water stress is moderate amongst the citizens [SR001-SR011; indicator 1.2].Nevertheless, water conservation strategies (indicator 1.3) such as grey water-reuse on a household level is widely applied [SR001-SR002-SR004], which is reflected in the city's low per capita water consumption of around 96 L person −1 day −1 ([SR006-SR011] [29]).The latter results from the fact that historically the region has experienced many droughts, and conservation strategies are engraved into the collective memory of the region [SR005-SR008-SR010-SR011-SR012-SR014-SR016].

Condition 2: Useful Knowledge
The perception regarding the availability, transparency and cohesion of the information varied considerably between the stakeholders.It was revealed that citizens have limited access to information (indicator 2.1) and that available information is difficult to locate (indicator 2.2).The regional meteorological information and the water reservoir data published by the Catalan Water Agency (ACA) and the regional administration are available but not presented in a way that is intelligible for the general public [SR011-SR014-SR009].Furthermore, much of the accessible information is not fully up-to-date or has a technical nature [SR004-SR007-SR010-SR012-SR014-SR016].At the city level there have been strong attempts to improve transparency and information services such as water saving tips on the back of water bills, education programs and conferences for all who are interested ([SR001-SR002] [30]).In general, the publicly available information is somewhat limited, which may be a by-product of limited incentives for stakeholders to communicate with citizens [SR007-SR010-SR011-SR012-SR014-SR016].Consequently, the available knowledge about water scarcity and reuse practices is not cohesive and demonstrates the existence of different perceptions amongst stakeholders (indicator 2.3).

Condition 3: Continuous Learning
The local water supplier CASSA has an advanced monitoring system (indicator 3.1) that can rapidly recognize alarming situations such as potable water contamination or leakages, and to some extent is also able to recognize long-term patterns of consumption, water flow and water quality [SR001-SR012-SR013].Nonetheless, a more regional, national or cross-sectorial monitoring and evaluation of the water sector is largely lacking, leading to fragmented knowledge [SR011-SR014].According to one interviewee, this is an important reason for the lack of transparency and the sharing of information between stakeholders [SR007].Evaluation of policy (indicator 3.2) occurs on an infrequent basis [SR008], it can be non-directional and susceptible to political shifts [SR013].The evaluation procedure is rigid, in particular with respect to the environmental laws, water distribution regulations and administrative aspects.In consequence, many norms are rather outdated and limit the application of water-reuse schemes [SR005-SR011-SR012].For example, despite the higher quality standards of treated secondary wastewater compared to other water sources, it is still prohibited to use treated secondary wastewater as a resource for drinking water [SR001].Criteria are largely based

Condition 2: Useful Knowledge
The perception regarding the availability, transparency and cohesion of the information varied considerably between the stakeholders.It was revealed that citizens have limited access to information (indicator 2.1) and that available information is difficult to locate (indicator 2.2).The regional meteorological information and the water reservoir data published by the Catalan Water Agency (ACA) and the regional administration are available but not presented in a way that is intelligible for the general public [SR011-SR014-SR009].Furthermore, much of the accessible information is not fully up-to-date or has a technical nature [SR004-SR007-SR010-SR012-SR014-SR016].At the city level there have been strong attempts to improve transparency and information services such as water saving tips on the back of water bills, education programs and conferences for all who are interested ([SR001-SR002] [30]).In general, the publicly available information is somewhat limited, which may be a by-product of limited incentives for stakeholders to communicate with citizens [SR007-SR010-SR011-SR012-SR014-SR016].Consequently, the available knowledge about water scarcity and reuse practices is not cohesive and demonstrates the existence of different perceptions amongst stakeholders (indicator 2.3).

Condition 3: Continuous Learning
The local water supplier CASSA has an advanced monitoring system (indicator 3.1) that can rapidly recognize alarming situations such as potable water contamination or leakages, and to some extent is also able to recognize long-term patterns of consumption, water flow and water quality [SR001-SR012-SR013].Nonetheless, a more regional, national or cross-sectorial monitoring and evaluation of the water sector is largely lacking, leading to fragmented knowledge [SR011-SR014].According to one interviewee, this is an important reason for the lack of transparency and the sharing of information between stakeholders [SR007].Evaluation of policy (indicator 3.2) occurs on an infrequent basis [SR008], it can be non-directional and susceptible to political shifts [SR013].The evaluation procedure is rigid, in particular with respect to the environmental laws, water distribution regulations and administrative aspects.In consequence, many norms are rather outdated and limit the application of water-reuse schemes [SR005-SR011-SR012].For example, despite the higher quality standards of treated secondary wastewater compared to other water sources, it is still prohibited to use treated secondary wastewater as a resource for drinking water [SR001].Criteria are largely based on the origin of the water source (e.g., freshwater or recycled wastewater) instead of formulating quality standards for different use categories.Finally, it was found that learning between stakeholders (indicator 3.3) occurs on the technical level, and often with respect to narrowly defined topics.It is not very common that cross-stakeholder learning takes place on a strategic, administrative or financial level [SR005-SR012].Many stakeholders are reluctant to share information due to the sector's competitiveness.Subsequently, cross-stakeholder learning is limited to a small alignment of stakeholders with similar interests [SR003-SR008-SR009-SR011].

Condition 4: Stakeholder Engagement Process
On the regional scale it is found that only a few and mostly conventional stakeholders are included in the decision-making process (indicator 4.1) which ultimately is bilateral and dominated by the national and regional government and ACA [SR002-SR004-SR005-SR007-SR010-SR011-SR012].Most stakeholders, including academia for instance, are often only informed or consulted instead of engaged in decision making [SR005-SR012-SR013-SR015].The decision-making process can be described as top-down with little opinion forthcoming from the local level.For example, local suggestions for more practical water quality norms for water-reuse schemes are not yet widely included in national guidelines.The water consumers or citizens have little active involvement or participation in the decision making process, which poses risks that their interests and core values can be harmed (indicator 4.2).However, citizen engagement is improving substantially (indicator 4.3) and new bottom-up initiatives as well as collaborations with grassroot organizations are appearing, such as ecological/green activist groups or basin associations (e.g., the Tordera River Basin Association and the Amics de l'Aigua civic organization).

Condition 5: Management Ambition
Sabadell aims to be one of the leading cities in water-reuse practices in Europe (indicator 5.1-[SR001-SR013] [28]).However, the city has to deal with fragmented, sometimes contradicting policies that affect water-reuse practices.In particular, different guidelines exist originating from different government levels resulting in insufficient management cohesion (indicator 5.3).The national and regional policy ambitions regarding water conservation are moderate and most interviewees indicated that the statutory compliance to these policies is suboptimal [SR003-SR010-SR015].Water quality and distribution norms are still determined by unilateral decisions, and a lack of sectorial, geographic and administrative alignment can be seen.Urban space construction permits have been released in the past even though they go against environmental efforts and restrictions for potential flood damage prevention [SR008].Low water fees for agricultural purposes contradict with the efforts to lower the agricultural sector's water consumption.Such discrepancies between national laws and the municipal administrative and geographical context can be observed and reflect a somewhat limited discourse embedding [indicator 5.2-SR007-SR009-SR014-SR016].Ultimately, this leads to major inefficiencies and barriers in implementation of reuse schemes [condition 9-SR013].

Condition 6: Agents of Change
Agents of change are found to have a limited impact on the overall governance capacity.There is little room for local entrepreneurial agents in the region's water sector (indicator 6.1).Water is ultimately publically administrated and even when subcontracted by a private company such as CASSA, the services are provided by monopolistic clusters and thus the sector is difficult to enter for entrepreneurs [SR007-SR008-SR009-SR012].There is some sector-specific entrepreneurial space, particularly with respect to the technology development [SR011-SR013-SR016].However, in most cases entrepreneurs who enter the market would have to work with a larger, already established stakeholder [SR001].Most expertise is accumulated in research centres [SR002] and many entrepreneurs export their goods and services abroad to areas such as Latin America [SR009].Most collaborative agents (indicator 6.2) are active in close collaboration between a limited number of traditional stakeholders [SR003-SR014].More recently, new and more inclusive collaborations are starting to take place.For example, public communication strategies with respect to household wastewater disposal have been established between CASSA, Sabadell City Council and ACA.This type of collaboration is often brief and established for very specific issues or events [SR001-SR016].A frequent barrier for closer collaboration is the divergent interests of the involved stakeholders [SR016].Finally, it is found that there does not exist a unifying long-term vision or strategy, which transcends different levels of decision making or enables continuity beyond the political mandate of 4 years [indicator 6.3-SR013-SR014].The leading body, ACA, is only recently recovering from a chaotic organizational period and thus their role as a visionary body has yet to be realized.At present, there is no entity that assumes the responsibility for leading the country's or region's water sector towards the implementation of water-reuse schemes or other water-conserving strategies.Rather, there is a great diversity in local initiatives that aim to implement water-reuse practices.

Condition 7: Multi-Level Network Potential
It was found that stakeholders have only limited room to manoeuvre (indicator 7.1) due to inter-organizational difficulties and the strict regulations and procedural demands of the ACA.Particularly with respect to the use or distribution of water permits, implementation is difficult [SR007-SR011].A distinction between the private and public entities can be observed.Public management has more rigid structures and procedures whereas private management typically has more room and independence to determine strategies and to experiment [SR001-SR010-SR013].Private companies can use this internally to remain flexible and to improve continuously [SR009-SR014-SR016].In Sabadell, room to manoeuvre is also ensured by a long-term contract between the water supplier CASSA and the city council.The division of responsibilities (indicator 7.2) in Sabadell is mostly clear but also somewhat inflexible [SR005-SR007-SR008-SR011-SR012-SR014-SR015].Water management is primarily the responsibility of each individual city council, with ACA and the Catalan government merely inspecting that municipalities comply with existing legislation.This leads to divergent, contradictory and overlapping approaches between different levels of decision-making [SR009-SR010-SR013-SR016].There are also gaps identifiable, in particular with respect to financial responsibilities.It is unclear which organizations will finance the necessary infrastructural refurbishments [SR014].ACA's authority is strong [indicator 7.3-SR008-SR011-SR015-SR016].However, some argue that ACA's procedural demands may hinder the progress of the water sector, and procedures sometimes resonate with political shifts [SR015-SR001-SR007] due to organizational and financial uncertainty [SR014].Partly as a result of this, the region of Catalonia lacks a clear centralized visionary leadership to enhance water-reuse practices [SR010-SR011].On the other hand, the role of ACA is primarily to act as an arbiter that balances and arbitrates between the interests of different stakeholders [SR008].However, with respect to water-reuse practices, strict control of existing regulations impedes further progression.ACA is in the position to unify the many different municipal approaches to implementing water-reuse schemes.Given the many experiences and promising results it would appear to be the opportune moment to develop a coherent legislative framework for water-reuse practices in cities.

Condition 8: Financial Viability
Basic water services are accessible for everyone.These services are either affordable or there are funds that support the most marginalized communities (indicator 8.1).Affordability for climate change adaptation is low because the possibility that citizens can apply to reduce the current and future impacts of climate change-induced water stress are rather limited.Although non-potable water reuse is feasible, legislation limits its distribution and only those living in a few specific areas of the city that possess dual networks can make use of it [SR001].The water consumer's willingness to pay (indicator 8.2) is however also restricted to basic services, and willingness to pay extra for an extension of the dual networks is relatively low, with citizens indicating that these extra investments should be financially supported by the government in consultation with the service provider CASSA [SR001-SR002-SR012-SR015]. The structure that can ensure financial continuity (indicator 8.3) of water-reuse practices (indicator 8.3) was observed to be very diverse among stakeholders and governance levels.At the national, Catalan, provincial and municipal level the continuity of funding for any climate change adaptation measures-including water-reuse practices-is largely susceptible to temporary, ad hoc, short-term policies [SR005-SR012-SR014].At present, infrastructure refurbishment requires an estimated €3 million in Sabadell [SR013].In order to build new infrastructure to promote the use of non-potable water, additional financial support will be required.

Condition 9: Implementing Capacity
Implementing capacity has been found to have both encouraging and discouraging factors.Some policy instruments (indicator 9.1), such as a progressive tax on water consumption or a connection tax for new water distributions, are being used effectively to incentivize low water consumption.Statutory compliance (indicator 9.2) is adequate, the legislation is generally respected and all stakeholders comply because noncompliance is an unnecessary risk [SR005-SR007].There is good understanding of the dynamics of reservoirs and a lot of experience from past drought events that can be employed to mitigate future drought events in the region.Water-reuse practice is increasingly being recognized as a promising and necessary climate adaptation measure.In municipalities such as Sabadell, important progress has been made to implement water-reuse schemes.Sabadell has a long-term mitigation strategy and the city has demonstrated a capacity to respond efficiently to water stress in the past.However, given that it has rained in the past months and that water reservoirs are full, ensuring water supply for the region for the next 2 years, the issue of increased water stress has temporarily been put aside [SR005-SR014-SR004].Hence, structural preparation (indicator 9.3) and infrastructural investments to mitigate water stress within a 30 or 50 year time frame appears to be an inevitable necessity.Some interviewees expressed their concern that the region is ill prepared for the impacts of climate change in the long run and current efforts seem to be insufficient [SR002-SR003-SR015].Hence, the ability of Catalonia to prepare for future water stress within the next decades will be largely dependent on the willingness to learn from and enable local water-reuse practices.

Discussion
In order to reduce water stress by a wider application of wastewater-reuse practices, major changes are required in the way the water cycle is governed at the local, regional, national and international level.Spain is currently experiencing this transformation, with different multi-level governance barriers and challenges emerging.Governance capacity is essential to collaborate effectively and to overcome these barriers.Our results demonstrate that Sabadell has gained considerable experience and has demonstrated a willingness to extend the reuse of municipal wastewater.The study has identified barriers and opportunities, revealing common factors and trends that are likely to manifest themselves in other municipalities not only in Spain, but throughout the Mediterranean and other water-scarce regions.

Coherent Legislative Frame Required to Support Water-Reuse
Through our case study of Sabadell, we found that legislative restrictions and inconsistencies imposed by regional and national regulations impeded the city's water reuse practices.In Europe, the lack of common water-reuse criteria has been identified as an important factor restricting the expansion of water-reuse practices [31].France, Cyprus, Greece, Italy, Portugal and Spain do have national policies on water reuse that focus mainly on agricultural irrigation.However, more focus on criteria for other applications are necessary to exploit the full potential of water reuse.Several regions in Spain already widely apply water-reuse [31].Royal Decree 1620/2007 provides the legal clearance and the Wastewater-reuse National Plan gives orientation and proposes procedures and criteria for the following applications: (a) urban uses such as garden irrigation, street cleaning, and fire fighting, as well as household applications such as toilet flushing; (b) irrigation of agricultural crops and use in aquaculture; (c) industrial uses such as in cooling towers and evaporative condensers; (d) leisure; and (e) environmental applications including aquifer recharge, forest irrigation, and wetlands maintenance [32,33].However, overly strict legislative water quality standards together with a demanding licensing process slow down Spanish municipal efforts to reuse treated wastewater [34].A reoccurring issue is that norms discriminate water, based on its source rather than on its properties, which is unfounded given the advanced treatment methods that ensure adequate water quality.In order to realize a widespread application of water-reuse practices, it is necessary to develop reclaimed water quality criteria per use category, independently of the water's origin [31].The legislative framework tends to be overly precautious, which does not reflect, nor support, the ambitions and efforts of local stakeholders aiming to implement this innovation.At present, municipal experiences with water reuse are not fully taken into account in the evaluation of regional and national policy.Moreover, periodical shifts in political parties further impede the development of a coherent policy that supports water-reuse schemes [SR013-SR014].Hence, guidelines and learning experiences are divided between a heterogeneous range of stakeholders, indicating that improved coordination through coherent regulation could boost the mainstreaming of municipal reuse of treated wastewater.

Realising Public Engagement for Non-Potable Water-Reuse
The public's awareness and understanding of the safety and applicability of reclaimed water is essential to the success of any water-reuse program [15] and requires public engagement [35].The vast majority of Spanish, European and Western societies have organized urban water systems, applying a centralized approach.Such systems allow for the large-scale collection and treatment of wastewater making it cost efficient due to their economy of scale [13].On the other hand, alternative, decentralized systems typically give citizens the responsibility to collect, treat or dispose their water.Decentralized reuse systems are in most cases a more expensive option , in particular in urban areas where such investments in centralized water infrastructure have already been made [36].However, there remains a persistent lack of public engagement in centralized water systems because the user, who is disconnected from water treatment, takes these services for granted, and is often not aware of the challenges and risks involved.The level of public acceptance is a key factor in the implementation of water-reuse schemes [15].Numerous reasons why the public has a tendency to be reluctant in supporting general water-reuse, potable as well as non-potable, have been studied across the globe [14].Common results are that potential consequences are unknown due to their (perceived) limited experience, implementation is seen as being irreversible, and citizens feel that they have little control over the process [35].The source of reused water is viewed as being unnatural and even toxic, which leads to the irrational, well recognized psychological "Yuck factor" [36,37], "naturalness" and "contagion" phenomena [38].Ultimately, public acceptance and support for water-reuse schemes is greatly a matter of the "interplay between trust, risk perception and emotional reaction" [38].The more the citizens are informed and the more that they trust the authorities the lower risk they perceive, and are thus more likely to support the schemes [39].
Building public support requires the construction of holistic narratives that appeal to the affective reactions as well as to the cognitive ones, changing the citizen's perception of wastewater as "dirty waste" to "resource" [38].It is therefore a task that requires multi-level collaboration, i.e., interdepartmental efforts, stakeholder engagement and citizen participation.It might be crucial to clearly distinguish between reuse for potable and non-potable purposes.Winning trust and earning support for water-reuse for potable purposes involves overcoming many hurdles.However, the potential to reduce domestic and industrial water consumption is greater when contemplating a situation that does not require drinking water quality standards, as is the case in Sabadell.Hence, the implementation of non-potable water reuse is often the first choice; for example, in Europe 97.7% of water reuse is for non-potable purposes.In Sabadell the public attitude towards non-potable water-reuse was found to be quite positive.This confirms earlier research in Sabadell [40,41].Due to previous experience regarding water stress, water conservation and the use of alternative sources for purposes such as flushing the toilet, washing the car or watering the garden, are already widely applied.It might explain the general positive public attitude towards water-reuse schemes at a municipal level.Hence, centralized water-reuse schemes may be more accepted by citizens if it is combined with household systems of rainwater harvesting, water conservation and grey water recycling.

Pricing Water
Despite a modest awareness of water safety and a general acceptance of water reuse practices, Sabadell's citizens and stakeholders were not willing to pay more in order to extend the duel distribution network in the city.Pricing water services is always a trade-off between the basic human right to affordable water and cost recovery.In fact, definitions of cost recovery can be misleading as cost can be deferred to the future or transferred to the environment, leading to environmental degradation.Hence, the question whether the price includes all operations, maintenance, and capital costs that can ensure freshwater availability in the long-term is decisive for the continuity of water services, in particular in water-stressed regions.Examples of external factors that can be excluded are water scarcity, social and financial issues, and environmental burdens such as wastewater or wastewater effluent disposal into the environment [15].At the same time, affordability for everyone has to be ensured [13] which emphasize the need for steering mechanisms.Reclaimed water is often priced just below the drinking water price in order to make it more attractive to consumers but this also poses issues concerning the recovery of costs [38][39][40][41].The expansion of Sabadell's water-reuse practices is hindered because the costs would result in a higher price of reclaimed water that could not compete with drinking water.Moreover, treated wastewater is still perceived as inferior by the consumer and thus few citizens are willing to pay the same or a higher price for it compared to water from primary sources.Major policy instruments such as a progressive tax on water consumption or the inclusion of the costs of reclaiming water in the consumer price for drinking water are used effectively in Sabadell to incentivize low water consumption and ensure affordability.At the same time, the existing water infrastructure requires substantial investments that may have consequences on the water price.Given the economic situation, it is a challenge to refurbish the existing water infrastructure, enhance water-reuse practices and maintain affordability of water services for everyone.In order to take up this challenge, co-financing from different stakeholders including citizens, local businesses, as well as funding from regional, national or European authorities might be required to combat water stress and continue water services in the long run.

Research Limitations and Key Priorities
The governance capacity analysis applied in Sabadell reveals a number of highly interconnected and interrelated governance processes.As a consequence, some of the framework's indicators interrelate as well.Some hypothetical "ideal" situations will not result only in very encouraging (++) indicator scores.For example, the role of entrepreneurial, collaborative, and visionary agents of change (indicators 6.1, 6.2 and 6.3) are context-dependent.Visionary agents may be more useful in times of crisis, whereas collaborative agents are more valuable in initiating new collaborations, and entrepreneurial agents operate best in flexible and open governance networks [21,22,24,27].Hence, situations may occur in which entrepreneurial and collaborative agents of change are very encouraging (++) while, as a consequence, visionary agents are less prominently active and score lower.Another important interrelation is between indicators 5.1 ambitious and realistic goals and 9.2 statutory compliance, because it is easier to comply with goals that are not ambitious [24].The governance capacity analysis applies a triangular approach of knowledge co-production consisting of three steps: (1) a desk study; (2) interviews and (3) feedback from interviewees.The detailed reporting and transparent research steps ensure reproducibility.However, because the number of interviewees is moderate and interviewees with different backgrounds sometimes contradict each other, the scoring justification for indicators 1.1 community knowledge, 1.2 local sense of urgency and 1.3 behavioural internalization, were limited due to the lack of available open source reports, documents and scientific literature.For these three indicators, a survey would provide more substantiated and accurate scores.

Conclusions
In line with the United Nations, we conclude that wastewater can be considered as a reliable and largely untapped resource that has much potential to alleviate water stress.In order to enable the wider application of wastewater-reuse practices, major changes are required in the way the water cycle is governed at the local, regional, national and international level.Spain is in the middle of a process of transformation wherein different multi-level governance barriers and challenges emerge.Through a case study in the city of Sabadell (Spain), this paper has aimed to identify the principal barriers, opportunities and transferable lessons that can enhance governance capacity in order to implement systems for the non-potable reuse of treated wastewater in cities.Overall, it was found that citizens in Sabadell do not fully understand the possible risks and impacts of water stress, but have a positive attitude towards the reuse of treated wastewater for non-potable purposes.In order to overcome the different operational barriers identified in the implementation of water-reuse practices, a coherent legislative framework is required that applies quality criteria per use category independently of the water's origin.Such a framework should be developed and implemented based on the local experiences of municipalities, such as Sabadell, through a regular evaluation process that transcends political cycles and overcomes the current fragmentation of interests, responsibilities and tasks between stakeholders.This requires the further development of governance capacity across multi-level governance layers.The results from Sabadell indicate that in particular with respect to knowledge provision, policy evaluation and learning, the development of a more coherent policy strategy for the wider application of water-reuse practices is required.These barriers and opportunities may provide learning lessons for other municipalities in Spain and throughout the Mediterranean and other water-scarce regions in the world.

Figure 1 .
Figure 1.Spiderweb of the City Blueprint analysis of the city of Sabadell, Spain.The scores range from 0 (poor performance; centre of the circle) to 10 (high performance; periphery of the circle).The results are reported in detail in the study by Šteflová [30].

Figure 1 .
Figure 1.Spiderweb of the City Blueprint analysis of the city of Sabadell, Spain.The scores range from 0 (poor performance; centre of the circle) to 10 (high performance; periphery of the circle).The results are reported in detail in the study by Šteflová [30].

Figure 2 .
Figure 2. Results of the governance capacity to alleviate water stress by wastewater-reuse schemes in the city of Sabadell, Spain.The 27 indicators are organized clockwise around the spider web circle by most limiting (−−) to most encouraging (++).

Figure 2 .
Figure 2. Results of the governance capacity to alleviate water stress by wastewater-reuse schemes in the city of Sabadell, Spain.The 27 indicators are organized clockwise around the spider web circle by most limiting (−−) to most encouraging (++).