Crafting futures together: scenarios for water infrastructure asset management in a context of global change

Drinking water supply networks play an essential role in protecting the human and economic wellbeing of the territories they serve. To ensure continued quality of service, organisations involved in water infrastructure asset management (WIAM) need to deal with a number of issues related to global change. This paper presents the results of an original interdisciplinary foresight approach carried out by a group of engineering and social scientists, in partnership with a number of stakeholders. The purpose was to examine various possible pathways for the future of a French territory. The full title of our foresight study is: ‘Supplying water destined for human consumption in Nouvelle-Aquitaine (France) up until 2070’. Four scenarios, as contrasted as possible, were designed based on five components: organisation and operation of the water supply service, social demands in terms of drinking water, the governance context, territorial dynamics, and the overall context. We then ran further simulations to visualise what a given infrastructure network would look like under each set of assumptions, and under different territorial configurations. One significant advantage of our foresight approach is the educational value it has for stakeholders and water managers. Foresight makes the future potentially visible and provides an opportunity to discuss it, in order to able to inform decision-making.


Issues, questions and analytical framework
The technical performance of a water supply service is typically monitored using three straightforward indicators: continuity of service (in terms of volume flow and pressure), sanitary quality of drinking water, and impacts on the natural and human environment. However, when combined with uncertainty and complexity, WIAM can become a 'wicked' policy problem. The ability to innovate is linked to anticipatory governance (Quay ), or the practice of

).
A more holistic approach is therefore required to enhance the traditional planning paradigm. With this in mind, our study aims to examine in parallel the technical dimensions of performance, developments in the demands made by society, governance issues, and the effects of climate change, thus promoting a new integrative approach to the study of WIAM. Its results and conclusions are designed to help policy makers, consultants and utilities to pave the way for proactive long-term decision-making processes, based on anticipation and foresight. In doing so, this research seeks to contribute to a broader body of reflection aimed at escaping the limitations of partitioned approaches and dayto-day management and decision-making.
Concepts and methods from a number of other studies reference the 'politics of anticipation' (Granjou et al. ).
Here, we present anticipatory governance as a new model of decision-making under high levels of uncertainty, based on the concepts of foresight and flexibility (Quay ).
'Foresight is an elaboration based on thoughtful methods of conjecture on the evolution and future states of systems whose future is perceived as an issue within their structured discussion' (Mermet ,p. 75 translated by the authors). We opted for the 'scenario method' (Bradfield et al. ), which simulates each part of a chain of events leading a system to a future situation, in a plausible and consistent way, and provides an overall view of this chain of events (Julien et al. ). Its advantages include its ability to deal with complex systems whose possible evolutions are only partially determined (Durance & Godet ), as in the case of drinking water services in the context of global change (Gober ).
We built an original, reflexive and integrative foresight methodology, 'weaving together' knowledge from a variety of disciplines. Our approach was also participatory and inclusive, as it involved researchers, practitioners, experts, politicians, policymakers, lay people, etc., to call on the Mermet ). This foresight provided the opportunity to reflect on WIAM strategies that (i) cover the issues of global change (climate change, shifts in the quantity and quality of resources available, technological changes, changes in consumption patterns, legislation, mobilities, lifestyles and ways of living, governance, etc.), (ii) heal the rift between the 'large' water cycle (river basin) and the 'small' water cycle (drinking water and sanitation) and make it possible to treat drinking water supply as an integrated whole (i.e. to consider interdependencies between territories, resources, infrastructures, service provided to users, management, normative systems, practices, etc.), and (iii) explicitly take into consideration the long-term issues (which means moving from programming to anticipation).

Selecting our case studies
Our case studies relating to the study of impacts of global change on WIAM were chosen based on five main criteria: (i) contrasted spatial configurations (urban, peri-urban, rural, coastal, economic activities) and dynamics (seasonal influence of tourism, metropolitan dynamics, etc.), (ii) contrasting types of water management and modes of organisation (public vs private water management, type of management organisation, water plan area (SAGEschéma d'aménagement et de gestion des eaux)), (iii) focused local issues (demographics, seasonal attractiveness, non-domestic water uses, cost of drinking water production, inter-sectorial conflicts for water resources, etc.), (iv) availability of data and quality of the information system for WIAM, and (v) contrasting finance and investment capacities. Island (see Figure 1). In any study of this type, a reasonable balance of 'internal' and 'external participants (i.e. respectively, researchers and stakeholders) is essential. To ensure this, our foresight group was made up of 22 people in total (twelve researchers in water engineering, statistics, economics and sociology, and ten stakeholderspolicy makers, water supply and groundwater managers, municipal representatives, a philosopher who acted as the 'uninformed', etc.).

Organisation of the foresight group
An initial one-day working session for researchers only was held in June 2018. A further four one-day workshops were organised for the entire foresight group over a 4-month period between October 2018 and January 2019. Between workshops, researchers worked individually to produce content to motivate debate.
The first step, at the researchers-only workshop, was to clearly identify the problem we were trying to address, and then break that problem down into smaller parts, which we referred to as 'components'. Following in-depth analysis and discussion, the initial definition of the problem was as follows: 'supplying water destined for human consumption'. The scope of this question is broad enough to cover a multitude of issues, be they industrial or agricultural in nature. As a spatial area for our study, we chose the Nouvelle-Aquitaine region, chiefly for the rich variety of situations it offers, but also because issues of governance are much harder to tackle on a smaller scale. As a timeframe, we opted for a minimum of 50 years, to allow for the general inertia of water supply infrastructure and networks. It was subsequently decided that the full title of our foresight study, or 'system', would be: 'Supplying water destined for human consumption in Nouvelle-Aquitaine up until 2070'.

Variables and components
During the researchers-only working session, time was spent reflecting on the 'components' of the 'system'. Scenarios up until 2070 were designed based on five components: (i) organisation and operation of the water supply service, (ii) social demands in terms of drinking water, (iii) governance, (iv) territorial dynamics, and (v) the structural context. Each component was then described using variables that matter for the future of drinking water supply in Nouvelle-Aquitaine in 2070 (Figure 2). At the end, each foresight scenario was made up of a total of 21 variables.
To ensure that scenarios are not purely a product of people's imagination, but rather part of a more thorough approach, foresight calls for a clear description of each variable. 'Variable' sheets were thus completed with the objective of establishing reliable and reflexive projections of the state of each variable within the system, based on assumptions made concerning the past and current states of the variable. This work, carried out collectively, sought to give credibility to the scenarios for decision-making purposes (Durance & Godet ). Exploring the future is not purely a matter of chance, since foresight is about the capacity to identify, beyond that which is clearly visible, the factors shaping changes (Godet & Durance ). The 15-page description of each variable therefore not only contains a retrospective analysis and assessment of the current situation, but also some 'dominant trends' (i.e. slow but steady changes), 'seeds of change' (i.e. trends currently fairly constant but likely to play a more significant role in the future) as well as uncertainties and 'wild cards' (defined by Petersen ()  Component-scale micro-scenarios were therefore designed, with the goal of building a narrative combining different assumptions relating to the future of the variables involved (Mietzner & Reger ). It is important to be able to map out a road between these assumptions that brings consistency, relevance and reasonableness to the nar- Based on the same principle, system-scale macro-scenarios were designed to represent a series of events occurring over time.

RESULTS
By combining the different pathways that could be taken by each variable, we designed micro-scenarios and, by combining these, we generated four macro-scenarios describing the possible situations for drinking water resources and infrastructures between now and 2070. Following this, these same scenarios were used for the simulation of future infrastructure needs.

Foresight scenarios
Once the skeleton of each scenario (i.e. the story-telling) had been created, the scenario itself was put into narrative form by adding the right 'binders', highlighting the driving and key variables and ensuring the scenario was coherent and consistent (Durance & Godet ; van Asselt et al. ).
These scenarios (S1-S4) are as contrasted as possible, based on scientific knowledge and participative animation. Heavy social demand placed on traditional water services has led the government to promote utilities managed by a national centralised agency, the cost of which is met through a specific tax on consumption (water users pay for water). A fixed tariff is applied to the entire country.
Bringing water management back into public ownership has made it much easier to coordinate with the services responsible for other areas of infrastructure. To ensure that water is shared out in the most equitable way possible, distribution networks are more and more interconnected. An ever-growing number of sensors are installed and shared databases are centrally used to monitor infrastructure and decide on how assets are to be managed.
S2: technocratic management led by regional planning The relatively high cost of these actions is met through the creation of a specific tax (water users pay for water), and through stringent application of the 'polluter pays' principle for all uses. Adherence to sanitary and environmental requirements pushes up the price of water, which is set at regional level and based on each users' financial situation.
A reduction in individual consumption, combined with changes to the agricultural production model, has allowed a significant amount of pressure on water resources to be alleviated. Conflicts between different water uses, particularly in terms of agriculture, are now confined to occasional localised incidents.

S3: pragmatic management based on trial and error
By 2070, the Nouvelle Aquitaine region has been affected by intense global warming for several decades. Marred by uncertainty surrounding raw materials and water availability, regional water services practice reactive management, with the aim of ensuring continuity of service through existing infrastructure. The priority is to ensure the quality of water at source, rather than investing in sophisticated and costly treatment programs. There is a general dependence on winter storage of water, which is often irregular in its availability, leading to intermittent excessive use of underground water sources.
Innovations in technology and organisation are used to enhance service performance. There is a move towards the use of sensors, both along the network and at user exit points of use. Consumption is monitored in real time and data are shared between services. The cost of introducing all of this new technology has pushed up the price of water.
The region has continued its swing towards more tertiary type activities, while continuing to cultivate highvalue irrigated crops. The Gironde department, where the city of Bordeaux is located, and coastal regions have continued to attract new residents, leading to lower populations in inland areas. This territorial inequality has led to a rivalry between urban and rural areas in terms of uneven demand for water (unequal territorial distribution of water resources) and non-uniform management of water networks and their level of performance.
EU regulations relating to raw water quality have become much more stringent, imposing minimum results and sanctions. Water users are called upon to restrict their water consumption through continuous monitoring, using both technical solutions and financial incentives.

S4: strategic and individualist management
In 2070, global warming will have reached very high levels.
Several developed countries have favoured investing in technological innovations rather than changing their production and consumption models.
In the Nouvelle Aquitaine region, water resources, sensitive to climate change, are less abundant and of poorer quality. This leads to an upsurge in conflicts of use.
Water utilities have developed safeguarding strategies based on technical innovation. Climate change tends to increase water consumption. Water management, now decentralised to various extents and fragmented, varies from one territory and set of users to another. Management efforts tend to be focused on collective and/or individual supply of raw water, with purification for drinking purposes delegated to (very) local organisations. The general consensus that public access to drinkable tap water is a universal right has slowly begun to fade.
Service performance is assessed based on economic criteria. Water price and service quality vary significantly from place to place, and depending on the level of investment. An absolute basic level of service is provided, which can be topped up with additional paid-for options. The growing number of people being disconnected results in networks falling into disrepair. A strategic renewal program is put together using an information system. Net migration to the Nouvelle Aquitaine region remains positive, but there is still an ageing population, with reduced quality of life throughout the region. The local authority continues to support intensive, high-performance farming based on significant levels of irrigation.

Simulating future infrastructure needs
Once we had obtained the outcomes from our scenarios, we ran further simulations to visualise what a given infrastructure network would look like under each set of assumptions, and under different territorial configurations.
The reason for this was that while our initial scenarios covered a number of 'structural context' and 'governance' issues at regional level, reasoning at this scale is not sufficient when examining potential infrastructure requirements, which ideally should be addressed at the smaller 'utility' level. To achieve this, we applied all of our scenarios to our four case studies.
Modelling was carried out using the Porteau software package, a specially-designed tool to study the hydraulic operation of pressurised looped water distribution systems (http://porteau.irstea.fr/). The software's first action is to model the current state of the drinking water distribution system. Our aim was to modify this modelling method to simulate how the system would operate for each foresight scenario, thus identifying: (i) areas in which local infrastructure would not be able to handle the demand placed on it by a given scenario, (ii) areas in which new infrastructure would have to be installed, and (iii) the most appropriate pipe diameters.
Different size parameters were used by the foresight group when creating their scenarios. Key considerations were the number of customers and the effective level of water consumption. One of the first things we did with this modelling approach was to distribute new subscribers spatially, using existing spatial maps and the urban development strategy from each foresight scenario. For example, in S3, the number of customers will be unevenly distributed between rural and urban areas. In S4, sharp rises in sea levels would likely place significant strain on construction sites close to the coast. With our method, the necessary network extensions to deal with these issues can be modelled. To ensure demand does not outstrip supply, consumption trends should be defined for each foresight scenario, as a daily profile and/or an annual volume. For example, in S1, there is a large (40%) decrease in annual consumption, whereas S2 shows only a 25% drop. S3 shows a stabilisation in the current decline in demand for water, while in S4, demand increases by around 20%.
To simulate how the system would likely behave during peak demand periods (instantaneous peak flow on a peak day), a daily peak coefficient was used. Table 1  Under each scenario, various other items affecting network construction can be added. These could be, for example, interconnections (in S1 and S4), dual network systems (in S2) or a dam construction project (in S3 for SIAEPA). Once these various modifications have been completed, the simulation can start. The objective of this tool is to solve problems such as low water pressure, an overuse of one resource, and to determine the adjustments needed by resizing the network in order to fulfil different performance criteria. Figure 3 shows the distribution of new consumers in Cestas for S4, illustrating the suburban colonisation of natural space. Figure 4 shows the effect of S4 on Oléron Island. As the sea level rises (following the IPCC, we assume a sea level

DISCUSSION
To support policy makers and WIAM organisations in assessing their preparedness faced with issues of global change, we aim to share and discuss various categories of linked results: (i) WIAM strategies and (ii) education and awareness-raising efforts.
Water infrastructure asset management strategies WIAM involves planning gradual changes to a network in order to (i) maintain, or even improve, the quality of service provided to users, while keeping outages to a minimum, reducing losses, and ensuring suitable water quality and pressure, and (ii) adapt its configuration (diameter and location of pipes) to suit levels of water available, demand for water, and wider territorial development goals. Any change of this sort being made to a water network will generally be slow: typically, the total annual length of pipes renewed is less than 2% of the total. In recent years, this renewal rate has been as low as 0.6% in mainland France.
And the cost of replacing pipes needs to be compatible with the multi-annual investment plan, which in turn defines the price paid by the end user.
In practical terms, annual removal from service and/or replacement of pipes can be as a result of excessively high breakage or leakage rates, or may also take place when the material they are made from no longer conforms to safety regulations (e.g. PVC pipes made before 1980 which are a source of vinyl chloride monomer, or pipes made of asbestos cement which are expensive and complicated to maintain). In some cases, pipe replacement has nothing to do with their actual physical state, but is carried out as  part of a broader plan to reconfigure a given network.
Finally, 'opportunistic' replacement may happen in parallel with work being carried out on other infrastructure (most often roadworks, but also gas, electricity, etc.). WIAM governance, which generally aims to work with rather than to be ruled by territorial development, has to be based on a strategic vision of the network and the capacity to anticipate its performance. This is where a There is still a certain margin for interpretation, meaning that one given scenario can be transformed into a variety of long-term simulations.
One of the other objectives of long-term simulations is to provide budget strategies based on rehabilitation, replacement and extension works. These strategies can then be used to define a strategic investment plan over a specific period: e.g. 5 years. This process (strategies followed by investment plans) can be repeated at the end of each period, enhanced each time with up-to-date knowledge.
Education and awareness-raising We held a seminar for water managers and policy makers to present our various foresight scenarios, and the methods used to create them ( Figure 6).  However, foresight is not a science, and we have no means of verifying whether or not our working assumptions will occur before the end of the foresight exercise (2070).
What is important is that the methodology be defensible and that it be presented in a fully transparent manner so that it may be subjected to suitable scrutiny. Although some people see foresight as a way to predict the future, in fact the aim is to help forecast the future or to clarify alternatives. More simply, foresight makes the future potentially visible and provides an opportunity to discuss it, in order to be able to inform decision-making. Of course, the future cannot be written and uncertainties surround us, but more than ever, designing WIAM strategies to deal with the challenges of global change calls for imagination.