This chapter introduces the strategic planning framework for drought risk management in the Paris metropolitan area. It provides an overview of the current appreciation of drought in the context of climate change. It then assesses the strategic planning capacity that enables effective drought risk management.
Adapting the Paris Metropolitan Area to a Water‑Scarce Future
Abstract
This chapter begins by reviewing existing assessments of drought risks (Section 2.2). their then takes stock and assesses the current institutional and strategic planning framework managing drought risk (Section 2.3). This analysis presents the regulatory context, as well as the roles and responsibilities of the various actors involved in managing drought risks. It analyses the robustness of current plans and strategies drawn up by these actors to respond to the challenges of drought-induced water scarcity, in accordance with their mandate. It likewise addresses the alignment of national and local sectoral policies with the aim of strengthening resilience to water scarcity.
Assessing the risk of drought-induced water scarcity is a prerequisite for drawing up a resilience strategy, as it makes it possible to set relevant objectives (for example, an acceptable level of risk). Assessing drought risks involves understanding how climate change could affect hazards, people, the environment, property and economic activity in a specific area. The assessment should cover potential hazards, exposure and vulnerabilities due to climate variations in order to evaluate any climate change-induced impacts (Box 3.1).
The Intergovernmental Panel on Climate Change (IPCC) defines climate risk as a combination of hazard, exposure and vulnerability. These terms are defined as follows:
Risk: Potential and uncertain adverse consequences of an event on something of value [...]
Hazard: The potential occurrence of a natural or human-induced physical event or phenomenon that may cause loss of life, injury or other health impacts, as well as material damage and loss [...]
Exposure: The presence of people, livelihoods, species and ecosystems, functions, environmental services and resources, infrastructure, or economic, social or cultural assets in places or in a context that could be adversely affected.
Vulnerability: The propensity or predisposition to be adversely affected. Vulnerability encompasses a variety of concepts and elements, including sensitivity, fragility and the inability to respond and adapt.
The hazard in question in this study is drought.
Source: (GIEC, 2022[1]).
To assess the risk of water scarcity, both the resources available in various climate scenarios and the demand for water must be forecast. This exercise should be based on robust scientific data on the hazard and take into account long-term climate forecasts. To assess the risk of water scarcity, demand for water at the regional level must be projected and compared with the resources available for a given time horizon. This type of study has been carried out in other countries (and basins), such as the United Kingdom, which has estimated the water shortage its population will experience in 2050 in the event of extreme drought (Box 3.2).
United Kingdom
Climate simulations were carried out at the national level to understand how water resources will be affected by climate change. Several drought scenarios were envisaged (e.g. from 5.8% to 25% probability of occurrence). An analysis of how demand for water will evolve for the United Kingdom as a whole and for the different regions in different scenarios was carried out at the same time. For example, the United Kingdom Environment Agency posits that if no action is taken by 2050, an extra 3 435 million litres per day will be needed to meet the demand for drinking water (i.e. almost 25% of the volume of water distributed by water operators in 2020). There are large disparities between UK regions, with the South East particularly affected (51.4% of the national shortfall in volume). This demand takes into account the change in needs in situations of drought with a 500-year return period, the threshold set by the British government. A sectoral risk study can be carried out based on these scenarios, because the needs of different sectors have been assessed.
Barcelona
When the city's climate strategy was drawn up, forecasts of demand and available resources were made. Based on a 4% increase in demand for water compared with 2018 and a 12% drop in surface water resources and a 9% drop in groundwater resources, the study concluded that Barcelona could experience a shortage of 34 billion litres of water by 2050 (18 billion litres of drinking water per year).
3.2.1. Considering long-term climate and socio-economic trends
Although studies have been carried out at larger geographical scales, no prospective study has been able to accurately assess the future impact of climate change on droughts in the Paris metropolitan area. At the national level, the Explore 2070 study carried out in 2012 provides an assessment of the risk of climate change-induced water scarcity by 2070 for various basins (Box 3.3). The study found that climate change would mainly affect the agricultural sector. The purpose of this study was to assess the impact of three theoretical adaptation strategies, all of which were considered insufficient to offset the expected effects of climate change (Ministère de l’Ecologie, 2012[5]) (Box 3.3). A second study was carried out in 2022 on the Seine river basin by the EPTB Seine Grands Lacs, a public body managing reservoirs upstream of Paris. The aim of this study was to assess the socio-economic impact of severe low-water conditions on this area. This study identified the sectors that benefit economically from low-water support and could be vulnerable if reservoirs become less efficient due to climate change. (EPTB Seine Grands Lacs, 2022[6]). While this study provides an assessment of the potential impacts of drought, it is limited to the area covered by EPTB Seine Grands Lacs, i.e. the rivers supported by the EPTB Seine Grands Lacs reservoirs. Abstraction from other rivers or groundwater are therefore not covered. Finally, other studies have considered climate change-induced water scarcity at the local level, but few have quantified the exposure or vulnerability of different stakeholders (Box 3.3).
The simulation of economic costs set out in Chapter 1 is based on studies carried out on a larger geographical scale and provides a general overview of the potential risks for the region. The cost analysis proposed by the OECD follows the approach taken for a prospective demographic and socio-economic scenario defined in Explore 2070 to model future human pressures on water resources. Similarly, the analysis considers the impacts of climate change on both surface water and groundwater. Nevertheless, the climate scenarios used are the same as those used by EPTB Seine Grands Lacs. It was therefore possible to make use of the flow rate and lake replenishment models used in the study conducted by EPTB Seine Grands Lacs. The definition of "impact" was also based on the approach chosen by EPTB Seine Grands Lacs and reflects the application of the existing regulatory framework applicable to drought situations.
Some actors in the region have also sought to assess the exposure and vulnerability of different economic sectors. This is the case, for example, for the regional administration, which published an analysis of the Paris metropolitan area’s vulnerability to climate change (Institut Paris Région, 2022[7]), and the City of Paris, which updated its assessment of the city's vulnerability to various climate hazards (Ville de Paris, 2021[8]), including drought, in 2021. This is also the case for a network of water operators operating in the region, which wanted to assess the robustness of the existing network. However, these studies are qualitative in nature and do not provide a precise, quantified assessment of potential impacts. For example, the regional study uses Explore 2070 scenarios to illustrate the theoretical vulnerability of drinking water supplies, the built environment, the energy sector and agriculture. The Institut Paris Région has also analysed the potential impacts of climate change on ecosystems, with a particular focus on drought. For example, this study found that watercourses are vulnerable to too highly concentrated wastewater discharges due to reduced flow rates. However, no quantified impact study has been carried out. This is the aim of the analysis in Chapter 1.
Although the risk has not been assessed in quantitative terms, the main actors in the Paris metropolitan area are aware that the risk is significant and growing. According to the OECD survey carried out among various public and private institutions involved in managing the risk of water scarcity in the region (Appendix 5.2), more than half of those surveyed have already had to take steps to respond to water scarcity, and 91% of those surveyed (Figure 3.1) believe that this type of risk will be more frequent by 2050. While droughts have been identified as the most likely cause of water scarcity, the respondents seem most concerned about conflicts over the use of water and increased pollution, which would make water resources less accessible. At the national level, a survey of French citizens in 2020 found that 66% of French people are worried about not having enough water in the future. This figure is up in 2018, probably due to the major drought event in 2019. This perception is similar at the level of the region (TNS Sofres-C.I. eau, 2020[9]).
Explore 2070
This study is based on the A1B climate scenario projections of the IPCC and on various demographic and socio-economic scenarios, to jointly analyse how demand for water and its availability will evolve over the medium-to-long term. The study transposed climate scenarios into hydrological scenarios, including surface water (flow rates) and groundwater (levels). Explore 2070 calculated the impacts of demographic and socio-economic scenarios with and without taking climate change into account, to isolate the effects of climate change. Lastly, the project defines three adaptation strategies: a demand reduction strategy, an intermediate adaptation strategy and an increased demand strategy, each of which reflects changes in water consumption for different sectors. For example, under the demand reduction strategy, the project hypothesises that drinking water consumption and industrial withdrawals would be reduced by 20% and that 100% of irrigated corn crops would be converted to a mix of less-water-intensive crops. While water withdrawals (excluding for energy) are expected to fall under the demand reduction strategy (by 33% to 39% compared with a trend scenario) and the intermediate strategy (by 13% to 23%), the project concludes that none of the adaptation strategies will restore a balance between the available resources and demand. Whatever the scenario, it seems that biodiversity and ecosystem services will be under pressure and that the industrial sector is likely to experience water shortages. The study also highlighted regional imbalances, with few problems on the Rhine, but impacts on the Garonne and Seine rivers. The Explore 2 project, published in 2024, updates the Explore 2070 hydrological scenarios and could make it easier for public actors to take ownership of the risks, enabling them to conduct vulnerability studies at the most appropriate geographical scale.
EPTB Seine Grands Lacs study (2022)
An assessment of the socio-economic and environmental impact of severe low water levels in the upstream Seine river basin identified vulnerable stakeholders in the study area and suggested avenues for improvement. To do this, EPTB Seine Grands Lacs reconstructed historical flow rates for certain rivers receiving low-water support from reservoirs. This reconstruction made it possible to assess how full the lakes would have been during critical events such as the droughts of 1921, 1976 or 1991. Analysing the impacts with and without support from the lakes during these critical events made it possible to quantify the economic impacts on various economic actors and consumers of drinking water in the Seine basin in the absence of these lakes. This study also used a model of possible droughts until 2050 to assess the possible impacts of climate change on surface water. EPTB Seine Grands Lacs also forecast probable water demand for this timeframe. Drought modelling to 2050 showed that the historical scenarios were probable and that the results of the historical analysis were therefore valid for the medium term. In the longer term, more severe impacts selected at the discretion of the study authors were simulated in view of the uncertainty surrounding the climate scenarios.
Sources of water scarcity risk according to administrations, local authorities and water users
Note: Respondents could choose more than one answer. Half of the 40 participants selected longer periods of drought, for example, but may also have chosen other responses. It is therefore the cause most indicated by a majority of those surveyed.
Source: OECD survey, see Annex A.
3.2.2. Challenges of assessing the risk of climate change-induced droughts
The lack of drought risk assessment in the region can be explained in part by the level of confidence in the ability of current protective measures to respond to future risks. Interviews conducted with various stakeholders in the region (see Appendices) reveal a high level of confidence in existing adaptation measures in the Seine–Normandy river basin (e.g. low-water support infrastructure), suggesting that there should be no need for additional investment in adaptation measures. This confidence is based on the perceived absence of historical impacts.
The absence of a quantitative assessment of the risk of water scarcity induced by droughts at the basin or regional level is a symptom of the many challenges that make it difficult not only to interpret climate models, but also to replicate and forecast water demand over time. Firstly, modelling the impacts of drought is a complex task for several reasons: the impacts of drought can be both indirect and widespread; there is a lack of historical data on the impacts of droughts; the dynamics that cause damage are complex; and impacts can have multiple causes, such as heatwaves. Among the challenges identified by the region's various actors (Figure 3.2), uncertainty about climate variability reflected by the range of possible climate scenarios for the Paris metropolitan area, incomplete knowledge about water withdrawals, and data reliability issues are among the main reasons for not conducting risk assessments.
Note: Twenty-two survey participants answered this question, none of them commercial users. Respondents could choose more than one answer.
Source: OECD survey.
Taking into account local specificities in forecasts and the uncertainty surrounding the projection of rainfall patterns are major challenges for the Paris metropolitan area. Depending on the climate model used, precipitation is forecast to increase by 20% or decrease by 20%, for example,1 with completely different impacts. This uncertainty is common to all regionalised forecasts and hydrological simulations.
When faced with this uncertainty, approaches that use different climate scenarios simultaneously make it possible to consider the range of possibilities and the corresponding strategies. These scenarios can be built using climate or hydrological data, such as that provided by Explore 2. This has been done, for example, in the Netherlands and the United Kingdom, to assess their risks in different climate scenarios in order to adapt to possible changes in climate trajectories (Box 3.4).
The Netherlands: Delta programme
The Delta programme is a national initiative launched in 2011 that brings together the national government, water agencies and local governments (provinces and municipalities). It aims to improve flood control and the preservation of fresh water to make the Netherlands resilient to climate change by 2050. This strategy combines short- and long-term measures. Short-term objectives are precisely defined by the government and long-term objectives evolve every six years, depending on the results achieved and how knowledge develops. The "Delta scenarios" are updated frequently by combining climate and socio-economic scenarios to reflect four different possible trajectories and thereby account for uncertainties. In each scenario, socio-economic impacts are calculated for different sectors, such as agriculture, water freight, industry and drinking water. This makes it possible to calculate the cost–benefit ratio of certain priority measures.
United Kingdom: Adaptive Pathways
The national framework for water resource management requires water operators in the different regions to draw up resilience plans for their networks. The operator Thames Water, which serves London and the rest of the South East, has developed nine scenarios to represent the full range of possible futures in terms of climate change, socio-economic development and housing. The first 10 years are considered relatively certain and only one scenario is proposed. This makes it possible to identify the no-regrets measures that need to be implemented as a matter of urgency and to undertake preparatory work to identify options that could be implemented at a later date. Depending on how socio-economic development and climate change patterns evolve, the plan will be reviewed every five years, based on an assessment of the results achieved.
Risk assessment challenges linked to water consumption dynamics
Water scarcity is a function of dynamics between the resources available and water consumption over a particular timeframe, which contributes to a drop in resources over the long term (e.g. winter water consumption contributing to low summer groundwater levels). It is therefore important to understand the dynamics that lead to water scarcity, in order to identify the levers that can be used to minimise its impact. To do this, it is necessary to have quantitative, geographical and temporal information about demand for water, so as to assess the cumulative impacts of abstracting water for different reasons. Some abstraction, such as for irrigation, is seasonal and the risk of water scarcity for agriculture could be linked to abstraction during the rest of the year, irrespective of hydrological conditions. Likewise, some marginal withdrawals have little impact on resource availability, but added together they put significant pressure on water resources.
There is currently not enough data on water abstraction to understand how current consumption patterns influence the water resources and hence the probability of droughts’ occurrences. At present, there are no studies to assess the cumulative impact of withdrawals on water resources or the level of abstraction that the environment can withstand. Withdrawals are declared on an annual basis and little monitoring is carried out to understand how they are distributed over the year (IGEDD, 2019[13]). The national abstraction database lists all withdrawals subject to declaration (7 000 m3/year in water distribution zones, or 10 000 m3/year otherwise). These are the only withdrawals that we have information on.
Numerous initiatives are under way to improve the availability of information about the region's resources and needs. The availability of Explore 2 data, for example, is a positive step in this direction, making it possible to establish probable resource availability scenarios. Information about withdrawals, and above all their cumulative impact on water resources, also remains inadequate. Studies are being carried out by drinking water operators at the level of the City of Paris and the territory covered by the regional Water Syndicate (Syndicat des Eaux d'Île-de-France, SEDIF). However, these data only concern drinking water. Lastly, the French government plans to improve the monitoring of agricultural withdrawals to generate more detailed information about the sector's needs and make projections that take account of climate change.
Assessing the overall risk of droughts remains a challenge. Environmental risk is currently assessed in qualitative terms, due to the lack of reliable projections on the use and spread of pollutants, the progressive effect of drought impacts on soils, and uncertainty about how the environment will react to a range of (often simultaneous) hazards. Similarly, modelling aquifers in the context of climate change remains complex.
Resilience to climate change-induced droughts is an indirect objective of water management under French law. "Resilience to water scarcity" refers here to the ability of the region to anticipate risks linked to water availability and minimise them over the long term by adapting to future climate conditions. The French legal framework sets out the objectives and principles of water management and climate change adaptation, which are then transposed to the various relevant administrative levels. It also defines the roles and responsibilities of national and local public bodies tasked with implementing policies to build resilience to the risk of drought-induced water scarcity. This section describes the law governing drought and what action the various actors involved in water policy and management are taking in this respect. It then focuses on the strategic objectives guiding action in the Paris metropolitan area and to what extent they are consistent with the sectoral policies deployed in the region.
3.3.1. Legal and regulatory framework
Resilience to climate change is governed by the Climate and Resilience Act, which does little to address the impacts of climate change on water. The Climate and Resilience Act sets out France's priorities for the ecological transition (France, 2021[14]). It defines objectives for accelerating the ecological transition and what local authorities should do to adapt to climate change. It introduces stronger environmental penalties aimed, among other things, at preserving the quality of water resources. Lastly, it addresses the issue of water and its sustainable management, emphasising the need to preserve resources and reduce excessive withdrawals and pollution. It does not however set any specific targets, with the exception of the objective of "net-zero increase in built-up land" by 2050, which should help support the region's resilience by improving the rainwater infiltration.
Taking into account the effects of climate change on water resources, on the other hand, is central to the Environment Code, which brings together all environmental legislation. The French Environment Code establishes a framework for the balanced and sustainable management of water resources, taking into account the required adaptations to climate change (Article L. 211-1). It specifies the administrative powers and responsibilities in relation to water management and the following key strategic principles:
Water management is centralised at the level of major river basins or catchment areas, under the authority of a basin coordinator prefect, and governance is co-ordinated. The 1964 Water Act on water distribution and pollution control also establishes the administrative framework for water management, which remained in effect in 2023, and is intended to reflect hydrological dynamics. The Act establishes administrative districts that are responsible for co-ordinating the management of resources, via basin committees comprising representatives of the central government and local authorities, water users (industry, farmers, consumers) and associations.
Water management is also based on quantitative and qualitative resource management objectives, which are subject to planning (1992 Water Act). Each basin, via its basin committee, must draw up a master plan for water development and management (SDAGE in French). The SDAGE, revised every six years, plans water policy and sets the objectives of water actors and the water agency to maintain good water status.
The Environment Code requires urban planning policies to be brought into line with basin policies, via amendments to the Urban Planning Code.
The law governs the financial resources of basins and establishes the "water pays for water" principle. Users who withdraw water pay a fee to the water agency, whose revenues are used to finance projects to restore watercourses and protect biodiversity. These projects are carried out by local authorities, industry, farmers or associations (1964 Act, then the 2006 Act on Water and Aquatic Environments).
Basins and municipalities have been legally obliged to uphold the right to water and take climate change into account since the entry into force of the 2006 Act on Water and Aquatic Environments (LEMA in French).
Although the French Environment Code promotes water management that is resilient to drought risks, the law does not set specific objectives for adaptation to climate change. In accordance with the European Water Framework Directive, the French Environment Code stipulates that "good water status" must be achieved in terms of both quantity and quality, i.e. a status able to meet the needs of humans and ecosystems, and therefore ensure the availability of water. Similarly, the Environment Code aims to balance abstraction and groundwater recharge capacity (Article L.212.1), preserve ecosystems and, more generally, protect water resources. The Environment Code provides no guidance on how to integrate climate risks into water management, how often to evaluate the strategy deployed by the water agency, or which objectives to pursue. It nevertheless calls for adaptation to climate change to be taken into account at the basin level. Integrating adaptation issues at the basin level involves taking proper account of its hydrographic and socio-economic characteristics.
To complement the sustainable water management objectives, the Environment Code also provides a framework for drought crisis management. The Environment Code specifies the objectives to be pursued in the event of a crisis and gives prefects the authority to regulate water use. This approach is common in neighbouring European countries, which have established drought management frameworks to minimise the severity of droughts and guarantee the supply of drinking water or protect ecosystems if a short-term drought is expected. This is the case, for example, in Spain (Estrela and Vargas, 2012[15]), where watercourse monitoring systems have been deployed to anticipate drought risks as far as possible.
3.3.2. Roles and responsibilities
Resilience to the risk of climate change-induced droughts is the responsibility of actors involved in developing climate policies and managing water resources. Climate policies are guided by central government and transposed at the various territorial levels relevant to water management. This section describes the roles and responsibilities of the key actors involved in developing a drought resilience strategy.
Note: EPTB Seine Grands Lacs: Etablissement Public Territorial de Bassin (Basin Management Agency) Seine Grands Lacs; DRIEAT: Direction Régionale et Interdépartementale de l'Environnement, l'Aménagement et des Transports (Regional and Interdepartmental Directorate for the Environment, Planning and Transport); SEDIF: Syndicat des Eaux d'Île-de-France (regional Water Syndicate); BRGM: Bureau de Recherches Géologiques et Minières (French Geological Survey).
Source: OECD.
National actors
The French Ministry of Ecological Transition and Territorial Cohesion is responsible for the strategic approach to water resource management and adaptation to drought risks. It draws up the public policies on water resource management that apply to the different basins and supervises their implementation at the regional level via its decentralised branches. It is also responsible for drawing up and monitoring the implementation of the climate change adaptation strategy.
The French Ministry of Ecological Transition and Territorial Cohesion is also responsible for Voies Navigables de France (VNF), the public body that manages, operates and develops most of the French waterway network. Waterway management involves not only work and infrastructure on the network (canals, locks, etc.), but also the provision of services such as tourism and power generation. VNF also plays an important role in resource management, anticipating the risk of flooding or low-water periods to optimise water management on the main waterways. In periods of severe low water, VNF can close certain routes to navigation.
The Ministry of Agriculture and Food Sovereignty is responsible for the sustainable development of the agricultural, food and forestry sectors. Its policies therefore cover the preservation of water resources. However, it is the common agricultural policy, decided at the European level, that establishes the key criteria for accessing the assistance schemes needed to build water infrastructure, for example, across the regions.
The Ministry of the Economy and Finance supervises the water agencies and is involved in regulating the "Cat Nat" natural disaster compensation scheme. The Ministry can also participate in the National Fund for the Management of Risks in Agriculture (Fonds National de Gestion des Risques en Agriculture – FNGRA), which compensates farmers for damage caused by agricultural disasters, including drought.
The integration of climate issues into sectoral policies, particularly those on water management, was strengthened by the creation of a General Secretariat for Ecological Planning (SGPE in French) in 2023. First established under the supervision of the Prime Minister in 2022, the Secretariat monitors and ensures the coherence of environmental policies and co-ordinates the various ministries. The General Secretariat for Ecological Planning is tasked with setting objectives for the ecological transition and proposing a roadmap for achieving them that specifies how to mobilise the various economic sectors and territories and how to measure the achievement of these objectives.
The creation of the General Secretariat for Ecological Planning is a promising step towards increasing France's resilience to climate change-induced droughts. Indeed, water scarcity affects all economic sectors, as the cost assessment in Chapter 1 shows. Moreover, the creation of the General Secretariat for Ecological Planning supports a long-term approach to planning, which is essential for integrating climate factors into water management.
Actors in the Seine–Normandy basin
Water agencies are responsible for managing water resources at the basin level and must take climate factors into account. In the region, water management policy is implemented by the water agency, the operational arm of a basin committee. The roles of these two bodies are presented below.
The Seine–Normandy basin committee is made up of public actors (40% local authority, 20% central government) and representatives of users and associations (40%). It establishes and approves the key priorities of the water management policy.
Seine–Normandy water agency is a state-owned public administrative body. It finances projects to protect water resources and the natural environment. The water agency operates under the supervision of the French Ministry of Ecological Transition and Territorial Cohesion and the Ministry of the Economy and Finance. The water agency receives water abstraction declarations from users and is partly financed by the fees paid for this use. The water agency plays a crucial role in building resilience to the risk of water scarcity, by generating knowledge, raising awareness among economic actors and local authorities, and providing financial support for the implementation of resilience measures.
Resource management at the level of the Seine–Normandy basin is essential to ensure that water management is integrated and relevant. The area covered by the basin aligns with real-world hydrographic characteristics, i.e. it extends beyond existing administrative boundaries. It is therefore well positioned for considering the principle of solidarity in relation to the upstream-downstream impacts of water abstraction, and for taking account of the physical, chemical and biological equilibria of aquatic environments. Finally, the governance regime established at the basin level enables all stakeholders potentially affected by water scarcity to co-ordinate.
The basin has basin management agencies (EPTB), water development and management agencies and syndicates that facilitate the co-ordination of activities over an area that aligns with the hydrographic reality. These syndicates help local authorities take a coherent approach at the basin level by co-ordinating and mobilising actors and providing information and advice in their areas of competence. Among the EPTBs, the Seine Grands Lacs EPTB handles flood protection and prevention, as well as low-water support, by means of four reservoirs. Members of this EPTB include: the City of Paris; the departments of Hauts-de-Seine, Seine-Saint Denis and Val-de-Marne; the Paris metropolitan area; the Grand Est region; and three conurbation communities.2
Regional actors
Decentralised government services
Decentralised government services, under the authority of the regional prefect, help to monitor drought risks and implement drought crisis management measures. Decentralised government services are the executive branches of ministries at the local level. For example, every year the Regional and Interdepartmental Directorate for the Environment, Planning and Transport (DRIEAT in French) brings together the various actors in the region to participate in water resource committees, to take stock of water resources after the summer period. This Directorate is responsible for anticipating droughts, communicating on the risk and co-ordinating prevention activities (DRIEAT, 2023[16]). The DRIEAT ensures that water policies are co-ordinated with health policies and waterway management activities and integrated into local sectoral policies. Finally, the regional prefect sets the key priorities and rules for drought crisis management.
In parallel, the Chief Commissioner, who is also the defence and security zone prefect for the region, a decentralised service of the Ministry of the Interior, is responsible for protecting the population and, therefore, for crisis management. The prefect works to prevent risks and contributes to crisis management by drawing up the civil protection response organisation (ORSEC in French) plan, i.e. emergency response operations in the event of natural or technological disasters (pollution, explosion, etc.), crises such as energy or essential goods shortages. Within this framework, the prefect is responsible for supplying drinking water to vulnerable people in the event of a major crisis. However, although the Prefecture has already drawn up a series of plans to address the risks of flooding, heatwaves or extreme cold, there is currently no plan to anticipate drought other than the provisions set out by the DRIEAT. Likewise, the defence zone has fairly effective tools for monitoring bodies of water and the risk of flooding but is unable to predict the risk of scarcity in the long term.
Despite their important operational role in anticipating risk, the approach of the French government's decentralised services is still rooted in crisis management rather than climate change adaptation. Although the DRIEAT is responsible for allocating water resources at the regional level, abstraction authorisations are not designed to take account of diminishing water resources over the long term. Similarly, the Prefecture has drawn up a series of plans to handle the risks of flooding, heatwaves or extreme cold, but not a plan to anticipate droughts beyond the provisions set out by the DRIEAT. During the OECD survey, the Prefecture nevertheless noted that a plan is being drafted for the distribution of drinking water, including looking into requisitioning sites or securing distribution ports.
Local authorities
Local authorities are administrative entities elected at the local level. They cover several administrative levels (Box 3.5), from regions to municipalities. All local authorities play a direct role in resource management. Responsible for the environment and development in the region, in 2020 the Paris metropolitan area’s authorities set up a regional group of experts on climate change and the ecological transition in the region. The group’s mission is to facilitate and promote the incorporation of scientific research and knowledge on the climate and biodiversity into decision-making. The Paris Greater Metropolis’s authority has jurisdiction over the management of aquatic environments and flood prevention (GEMAPI). This gives it the power to undertake development planning activities affecting the basin and watercourses and makes it responsible for tackling the risk of flooding due to watercourses bursting, for restoring ecological continuity and for preserving wetlands. As part of its remit, the Paris metropolitan area considers how dry periods affect small watercourses within its territory when implementing its strategy and its planning activities. Finally, cities are responsible for distributing drinking water for human and economic needs and for sanitation. They can therefore increase the resilience of their population and economic sectors given their responsibility for urban planning, risk awareness and access to water and sanitation infrastructure.
France is divided into several administrative levels, each with specific powers and responsibilities:
Regions: Regions are the largest administrative division. There are 13 regions in France. They are responsible for economic development, territorial and environmental planning (regional natural parks, waste management, transport, etc.), education, vocational training, transport and culture. They are also responsible for managing European funds. The Paris metropolitan area is one of the 13 regions.
Departments: Departments are administrative subdivisions below the regional level. Their main responsibilities include social services (such as child protection services and social assistance), departmental roads, secondary schools, emergency services (fire service) and health policies. In the past, the departments were responsible for sanitation. The region has eight departments.
Métropoles (“Metropolis”): These are groups of municipalities with a strong urban influence. They have broader powers and responsibilities than other public intermunicipal co-operation bodies, notably in the areas of public transport, urban planning, housing and economic development. The Paris Greater Metropolis comprises 131 municipalities.
Municipalities and cities: Municipalities are the smallest administrative unit in France. They have a local remit over areas such as the civil registry, urban planning, social infrastructure, local road maintenance and access to critical services, such as water. The region has 1 276 municipalities. Municipalities can join together in administrative bodies to manage shared responsibilities, such as sanitation and waste management.
3.3.3. Strategic framework
Building resilience to drought-induced water scarcity requires the development of a robust strategy for each actor involved in water management. A robust strategy must take climate change into account, establish an acceptable level of risk and consequently identify risks that need to be avoided (prevention) or transferred. Finally, a robust strategy identifies the resources (human and financial) needed to achieve the objectives set.
National strategic framework
Climate change adaptation plan
Resilience to climate change is guided by the National Climate Change Adaptation Plan (PNACC in French). The PNACC drawn up by the Ministry of Ecological Transition and Territorial Cohesion for 2018-22 aims to adopt objectives and measures to adapt to a climate consistent with a global temperature rise of 1.5° to 2°C compared with the 19th century (Ministère de la Transition Ecologique et de la Cohésion des Territoires, 2018[17]). The plan has been designed around six key priorities aimed at improving the governance and management of adaptation policies; improving knowledge of climate risks, prevention and resilience; promoting environmental preservation; reducing the vulnerability of economic sectors and; developing France's international policy on adaptation to climate change. The PNACC was being revised at the time of the study, and the next version is expected to use a climate scenario with a temperature rise of 4°C in France (3°C worldwide) (France, 2022[18]).
The PNACC addresses water-related challenges and recognises the vulnerability of certain economic sectors, without setting specific resilience targets. Its assessment of drought risks is qualitative, in the absence of detailed information about possible impacts. One of the plan's objectives is to increase the information available on water-related risks. However, an estimated water deficit of 2 billion m3 by 2050, at constant demand, is mentioned, as is the likelihood of more frequent and severe droughts, reduced low water flow rates and increased pressure on water resources. The vulnerability of certain sectors is also highlighted, such as tourism, agriculture, mountains and ecosystems. The PNACC does not set specific resilience objectives but does express a desire to strengthen France's resilience to a drop in water resources by focusing on demand reduction, efficient use, upstream resource regulation, improving water quality for health security, and ecosystem preservation. Indeed, the plan recognises that government action is still too focused on crisis situations.
The PNACC strategy has enabled progress to be made in managing the risk of climate change-induced droughts. The PNACC identifies ways to strengthen France's resilience. For example, it aims to develop risk-related knowledge by identifying key actors, encourage regional mobilisation via regional adaptation committees and facilitate consultation for strategic resource management. The organisation of the Assises de l'Eau (Water Conference) in 2018 was consistent with this approach. The PNACC also provides for the co-ordination and monitoring of the plan's implementation. In 2020, an initial assessment of the PNACC highlighted the progress made (e.g. the launch of Explore 2, river basin adaptation strategies and the development of nature-based solutions) but did not identify any areas for improvement.
The Action Plan for Resilient and Co-ordinated Water Management
The national strategy for adapting water management to climate change has been strengthened by an Action Plan for Resilient and Co-ordinated Water Management (or "Water Plan"). Designed as a roadmap, this plan provides an opportunity to involve all sectors in implementing a resilience strategy and setting up a monitoring mechanism. This approach of co-ordinating efforts and developing a national strategy has also been used in other countries, such as Germany, which adopted a national water strategy in 2023 and the Netherlands, with its national Delta programme. Other countries, such as Australia, have a national drought response strategy, but focus on a single sector (Box 3.6).
Germany
Germany ran a two-year national consultation on water (2018-20), involving over 200 participants from industry, water operators, agriculture, the research sector, associations, federal states and municipalities, in collaboration with the German Federal Ministry for the Environment. Following this consultation, the government adopted a national water strategy that examines the challenges that Germany's water sector might face by 2050 and identifies 10 strategic priorities to ensure Germany's resilience to water scarcity by then. This strategy incorporates the challenges identified in Germany's Action Plan on Nature-based Solutions for Biodiversity and Climate. In addition, the strategy addresses the importance of safe and reliable water supplies and good river quality as drivers of economic development.
The Netherlands
As part of the Delta programme, the freshwater supply strategy sets out the challenges and measures to be implemented to guarantee access to these resources until 2050. Launched in 2011, this programme is regularly updated to take account of new challenges facing the country. Questions around water scarcity and climate change adaptation have been integrated into the Delta programme, which was originally more focused on flooding. A national strategy for the resilience of freshwater supplies to climate change is expected to be adopted by 2027.
Australia
In 2018, the Australian government approved and signed a new national drought agreement. This agreement sets out an approach to drought preparedness, response and support that involves the country's various states and regions. The agreement focuses on preparedness and climate change adaptation. Australia published its Drought Response, Resilience and Preparedness Plan in 2019, which reflects these objectives. This plan specifies the funding available to increase the country's resilience, particularly in the agricultural sector.
The Water Plan follows on from two similar attempts to take account of climate issues in water management, both of which had little impact. In 2018, the Ministry of Ecological Transition organised the Assises de l'Eau to develop, among other things, a strategy for adapting water management to climate change (Box 3.7). This conference led to the adoption of a pact designed to improve water resources, with a set of quantitative objectives for demand reduction and water resource optimisation. The pact was not based on any specific assessment of future risks, but proposed steps towards conducting one, as well as ways to improve governance. The measures proposed have not been followed up to any significant extent and have not led to any notable progress, such as the tripling of unconventional water volumes initially planned. Similarly, in 2021, the French Ministry of Ecological Transition and Territorial Cohesion, in collaboration with the Ministry of Agriculture and Food Security (MASA in French), organised an agricultural Varenne (ministerial consultation initiative) on water and climate change adaptation. The Varenne is intended to be the operational arm of the Assises de l'Eau for the agricultural sector (Box 3.7). It inspired a decree (France, 2022[22]) to improve the anticipation of risks by managing water resources outside low-water periods.
Assises de l'Eau
The Assises brought together local elected representatives, public water actors (basin committees, ministries), associations, companies and the research sector and users (farmers, civil society, etc.) over 18 months to discuss how to adapt water management to climate change. The levers identified include:
expanding local authorities' remit
strengthening co-operation for efficient water-resource-sharing
strengthening behaviour change communication.
For each lever, a set of actions is identified, as is the source of financing for implementing the pact, such as investment programmes.
Agricultural Varenne on water and climate change adaptation
In 2021, over six months, the Varenne mobilised 1 400 people from the agricultural sector, local authorities, central government, the research sector and associations. Organised around three working groups, this consultation proposed a set of recommendations to better anticipate climate risks, strengthen the resilience of the agricultural sector and collaborate better in identifying the water resources needed for agriculture.
Source: (France, 2022[23]).
The Water Plan proposes a coherent theoretical framework to strengthen France's resilience to droughts. Firstly, the plan promotes a risk prevention approach, reflected in the priority given to demand reduction, resource optimisation and water quality (Table 3.1). These objectives are the plan's three strategic priorities. Each of these priorities is supported by measures, for which actors are identified and implementation dates proposed. In addition, the Water Plan identifies the resources to implement this strategy. For example, it plans to give more powers and responsibilities to local actors and to review the regulations governing the declaration of water withdrawals, with a view to improving data availability. It also identifies financial measures and how to release additional funds to achieve the objectives. However, how resources will be allocated and on what basis funding will be granted for these measures remains unclear. Finally, efforts to implement the Water Plan are to be monitored regularly, with the results reviewed by the National Water Committee. Three reviews have already been carried out, at three months, six months and one year after the plan was published. These reviews demonstrate the government's willingness to implement the measures, given the mixed results of the Assises de l'Eau.
Although the Water Plan is aligned with the Assises in terms of its approach to droughts, it does not identify any specific resilience objectives. The plan does take climate change into account but is not based on a risk assessment. The plan recognises the likelihood of more severe droughts, and lower low water flow rates and groundwater levels, but it is difficult to assess whether these trends will affect water use and, if so, how they would do so (i.e. rare, periodic, severe). The Water Plan sets reduction targets, which are certainly quantitative and measurable, but which are not consistent with achieving an acceptable level of risk or a resilience objective. It does not provide for an assessment of the expected effectiveness of the plan as regards groundwater levels, groundwater recharge or water availability. As a result, the demand reduction and optimisation objectives, while relevant, might prove insufficient to mitigate the risk of water scarcity at the basin level. In the United Kingdom, for example, the government requires water operators to be resilient to a once-in-500-year drought by 2040 (Box 3.8). Demand reduction and resource optimisation strategies are then calibrated to achieve this resilience objective.
In the United Kingdom, water resource planning is carried out over a 25-year period, with the aim of balancing the resources available and demand for water. This exercise must take account of climate change and ensure the water supply is resilient, i.e. not reaching a drought crisis threshold that would restrict or even prohibit most uses. To this end, the National Infrastructure Commission calculated that by 2050, there could be a shortage of 4 billion litres per day in the worst-case climate scenarios considered (500-year return period). This objective serves as a starting point for the development of a resilience strategy and provides measurable targets for reducing water consumption and optimising existing resources. This approach is implemented within the United Kingdom's regions.
Although the objectives laid out in the Water Plan will be key to reduce vulnerability to water scarcity induced by droughts, it does not sufficiently account for the long-term challenges posed by climate change. When the French government presented its Water Plan, it stated that it was primarily designed to respond to the challenges of 2023. Indeed, the plan looks ahead to 2030. While it is effective and realistic to set short-term objectives, a longer-term outlook would make it possible to identify possible trajectories and monitor changes in the risk of scarcity under various adaptation scenarios. By way of comparison, the United Kingdom has established a 25-year outlook for resource planning (GOV UK, 2023[26]) (Box 3.8). The adaptation trajectories proposed by the United Kingdom then take the form of multiple scenarios, making it possible to integrate different timescales and risk levels. Among other things, this approach mitigates the uncertainty associated with climate change and helps identify not only priority no-regrets measures, but also longer-term options that it might be beneficial to anticipate (Box 3.4).
Local strategic framework
Seine–Normandy river basin resilience strategy
At the basin level, the question of climate change is at the heart of the Master Plan for Water Development and Management (SDAGE in French). The SDAGE is a water management planning tool covering a six-year period. It is drawn up at the basin level and adopted by the basin committee with the aim of achieving "good status" for water bodies (Box 3.9). Anticipating and preventing water scarcity is therefore central to the SDAGE's approach. Moreover, the 2022-27 SDAGE for the Seine–Normandy basin proposes five strategic goals for the basin, one of which is to ensure the resilience of territories and the balanced management of water resources in the context of climate change. To achieve this, the SDAGE is based on a set of existing climate projections for the basin, reflecting the work on Explore 2070, as well as more recent modelling of possible droughts looking ahead to 2050 (Boé et al., 2018[27]). The SDAGE is therefore designed on the assumption that available water volumes will decrease, without specifying the expected impacts. The other four SDAGE goals are indirectly related, given that they concern protecting the environment, reducing pressure on water resources and reducing pollution. This strategic document highlights the close links between resilience to water scarcity and sustainable water management.
The basin committee uses two main indicators to establish the good quantitative status of resources and therefore that sufficient water will be available. For groundwater, the ratio between groundwater abstraction and average groundwater recharge is calculated. Above 15%, this ratio indicates a fragile balance between water resources and the risk of scarcity if abstraction continues. For surface water, we compare the volume of consumption during low-water periods in the month with the five-year lowest flow (lowest average monthly flow occurring on average once every five years). If this ratio exceeds 20%, there is a risk of imbalance if additional pressures emerge. These indicators can be used to identify areas of fragility and amend water abstraction authorisations in anticipation of droughts.
Water management planning at the basin level is also based on the basin's climate change adaptation strategy, which establishes the basin's priorities for resilient and sustainable water management. Resilience to the risk of water scarcity is central to the strategy, which prioritises further reducing demand to cope with the risk of climate change-induced water stress. The strategy also prioritises – in order – safeguarding water quality, protecting ecosystems, combating flood and rising sea level risks, promoting groundwater recharge, combating heatwaves and, finally, supporting local actors.
The objectives identified by this strategy to address the risk of water scarcity induced by droughts are similar to those of the Water Plan. Indeed, its main objectives are demand reduction, resource optimisation prioritising nature-based solutions, and water quality preservation. The adaptation strategy adopted in 2016 by the basin committee was updated following the publication of the Water Plan, to transpose the plan's objectives to the reality of the basin. For example, the objective of a 10% demand reduction in abstractions at the national level was transposed into demand reduction objectives for the industrial sector (4% reduction), drinking water (14% reduction), the agricultural sector (stable) and canal supply (stable) (Agence de l'Eau Seine Normandie, 2023[29]).
The adaptation strategy aligns with the objective of increasing resilience to droughts but remains vague in terms of expected long-term impacts. The strategy is based on a variety of climate scenarios and assesses the possible qualitative impacts of climate change for the various stakeholders in the basin. However, it does not present a precise risk assessment quantifying the balance between needs and resource availability, as suggested in 3.2. The resilience objective pursued by the Seine–Normandy water agency could be understood to be water bodies achieving "good status", although only qualitative criteria are established for surface waters. It is however difficult to gauge whether the objectives pursued will be sufficient to achieve such "good status" over the long term. Finally, the climate change adaptation strategy does not present a long-term trajectory, given the planning periods under SDAGE, which establishes the basin's operational objectives over six years. Nevertheless, the strategic objectives of each actor in the basin have been defined in detail and the basin committee is continuing its efforts to engage and mobilise local actors. To this end, the basin has trained and raised the awareness of sub-basin actors on its objectives, with a view to developing local strategies. More than 500 actors (local authorities, businesses, farmers, chambers of agriculture, associations, etc.) have signed up to the basin strategy, a clear example of how the basin has facilitated the implementation of activities (Agence de l'Eau Seine Normandie, 2023[29]). An evaluation of policies at the basin level also reveals a stronger trend in favour of demand reduction in various sectors (e.g. industry, Chapter 2).
Local authority resilience strategy
In 2022, the Paris metropolitan area ’s authority published its climate change adaptation strategy (Région Ile-de-France, 2022[30]). This strategy has three main objectives: protecting vulnerable people, protecting ecosystems, and protecting the economy. The region aims to take a cross-cutting and systemic approach to risk, based on a clear governance regime.
Its approach to droughts focuses on reducing the vulnerability of economic sectors, citizens and ecosystems. The regional climate change adaptation plan (Région Ile-de-France, 2022[30]) identifies droughts primarily as a risk linked to clay shrinkage and swelling and to resource-sharing. However, recognising that water resources are likely to decline due to climate change, the strategy proposes concrete measures to reduce the vulnerability of ecosystems, encourages judicious water management in the agricultural sector and promotes more-efficient water management approaches. This strategy does not however specify a resilience objective, given that it does not include a specific risk assessment. It also sets out the financial resources needed to implement the proposed measures (a budget of EUR 1 billion euros by 2030), as well as support for the different economic sectors and local authorities. For example, guidelines have been drawn up to support local authorities with their adaptation strategies.
The Paris Greater Metropolis has also focused its approach on reducing vulnerability. For instance, it published its Climate Air Energy Plan (PCAEM in French) in 2018, which included an analysis of vulnerability to various anticipated climate hazards. Drought is not considered to be one of the main risks, other than insofar as it relates to the risk of clay shrinkage and swelling (Métropole du Grand Paris, 2018[31]). However, drought is identified as a risk for drinking water supplies, notably due to their dependence on surface water. Paris Greater Metropolis also anticipates significant impacts on agricultural systems and green spaces. The PCAEM recognises the need for a more detailed analysis of the balance between water needs and resources and aligns with the local authority approach of reducing drinking water consumption.
Reducing vulnerability is also the approach taken by the City of Paris, which has, for example, drawn up a resilience strategy that identifies challenges affecting rivers as one of its six priorities. Low water levels are mentioned as a significant challenge affecting drinking water supplies and economic activities that can only be tackled through co-operation at the basin level. However, no resilience objectives are specified for water scarcity, and the risks associated with declining water availability are mainly addressed by fairly general urban planning and water quality protection measures (Ville de Paris, 2019[32]). The City of Paris is also expected to approve an ambitious Climate Plan for 2024-30, which commits to reducing water withdrawals by 15% by 2030 and provides for the prioritisation of uses and the diversification of water sources (see Chapter 3). Water quality challenges are also central to the new plan (Ville de Paris, 2023[33]).
Although the risks of flooding and heatwaves seem to be better known, the revision of local authority plans and strategies currently under way could improve how they address the risk of drought-induced water scarcity. The Greater Paris metropolis’ Climate Air Energy Plan, for example, has identified flooding as the main risk for its territory and has carried out a geographically detailed risk assessment. Heatwaves are the second highest priority hazard for the Paris metropolitan area, given their past impacts, particularly on vulnerable people. Likewise, the City of Paris has drawn up a Paris Pluie [Paris Rain] plan and a heatwave plan. In 2023, as part of the overhaul of its resilience strategy, the city carried out a full-scale exercise to enable it to respond to future heatwaves (called "Paris at 50 degrees") (Ville de Paris, 2023[34]). Both the Paris metropolitan area and the City of Paris are reviewing their PCAEM and resilience strategy, and plan to take greater account of challenges linked to drought and the resulting water scarcity by 2024.
Drinking water operators
The region's water operators are also a pillar of the region's resilience. For example, the regional Water Syndicate (SEDIF in French), the largest water operator in the Paris metropolitan area, has a Continuity and Drought Relief Plan describing the warning systems and structures in place to respond rapidly and effectively to a high-risk situation as a result of severe low water affecting one or more rivers supplying drinking water production plants. SEDIF has also drawn up a "last resort" plan, the aim of which is to guarantee that it can supply a minimum 5-10 litres to users by drawing on underground resources, such as the Albian aquifer (SEDIF, 2022[35]). Similarly, Eau de Paris has water storage margins capable of supplying the population for two days and relies on a range of water catchments. Eau de Paris is working with the French Geological Survey (BRGM in French) to assess the sustainability of its resources, taking into account climate change. Eau de Paris monitors rivers and other watercourses to anticipate possible restrictions and adapt its strategy. Lastly, Eau de Paris has drawn up a Climate Plan, a Resource Protection Plan and a Biodiversity Plan, all of which help ensure water availability, notably by limiting pollution and preserving ecosystems (Eau de Paris, 2021[36]).
Note: For the purposes of this study, only the towns/cities of Sceaux, Paris, Cergy and the Cergy-Pontoise conurbation community were surveyed. Research was also carried out on the strategies and plans of other towns, such as Montrouge, Fontainebleau, La Plaine and Créteil.
The current drought resilience strategy that prevails across France is key to reduce stakeholders' vulnerability. Indeed, all the policy actors involved in water resource management have drawn up a strategy that addresses drought risks. The strategies adopted at the local level are aligned with the objectives set out in the government's Water Plan. The strategic priorities pursued at all geographical and administrative levels are clear. The priorities relate to water demand reduction, resource optimisation and improved water quality. The actors have all been identified at the relevant level, and financial and human resources are available to support the implementation of the various resilience strategies.
However, a long-term approach capturing climate projected risks is missing. None of the strategies specify a resilience objective to be achieved, with the possible exception of the water agency, which must achieve good status for water bodies. None of the strategies are based on a projection of the impacts or costs of climate change. In the absence of a risk assessment and an explanation of what is and isn't acceptable in terms of impacts, any resilience strategy could be under- or over-calibrated relative to the expected risk.
3.3.4. The alignment of the national resilience strategy and the sectoral policies of the Paris metropolitan area
Drought resilience requires that economic actors and urban planners alike adopt coherent policies. The Water Plan's strategic objectives of reducing water demand, optimising water resources and limiting pollution affect all economic sectors that use water, such as agriculture, energy, industry and water transport. Similarly, to optimise water resources, water issues must be integrated into urban planning policies, as set out in the Seine–Normandy basin master plan for water development and management. This section analyses how sectoral policies implemented in the region align with the objectives of reducing the region's vulnerability to droughts’ risks. It also examines the role of the various national, basin-level and regional actors in aligning these policies.
Urban planning policies
The Master Plan for Water Development and Management (SDAGE in French) of the Seine–Normandy basin is designed to ensure water policies align with regional planning and development policies. Local authorities must align their planning policies with the resource and environmental protection objectives set out in the SDAGE. The SDAGE was drawn up as part of a participatory process, notably with the support of local authorities. In fact, local authorities' urban plans make it possible to identify and locate landscape features, demarcate neighbourhoods and zones for sanitation and rainwater management, and set land-use coefficients that have a direct impact on ecosystems and the preservation of water resources. In this way, they contribute directly to the natural storage of water, to reducing demand for water, and to water quality.
The overarching priorities of the Seine–Normandy basin Master Plan for Water Development and Management are to some extent reflected in the economic development documents of the region and the Paris metropolitan area:
The regional Master Plan (SDRIF in French), which presents a framework for the development of the Paris metropolitan area, seeks to preserve aquatic environments (e.g. reducing pollution as a result of house building; recovering water) and focuses on the concept of restrained land development (sobriété foncière) to meet national targets of a net-zero increase in built-up land. The SDRIF forecasts population growth of 50 000 inhabitants per year in the region until 2040, which will impact the construction of new housing and the development of transport networks. Restrained land development is essential if the region is to limit the pressure on water resources and facilitate rain absorption and groundwater recharge. The regional authority is supporting projects to reclaim brownfield sites in the Paris metropolitan area in order to combat urban sprawl, preserve the environment and increase agricultural land. It is also encouraging the renovation of existing buildings. In 2024, the region is due to adopt a new Environmental Master Plan for the region (SDRIF-E 2040 in French) to take greater account of environmental issues.
The Territorial Coherence Plan (SCoT in French) sets out the 20-year development strategy for the territory formed by the 131 municipalities of the Paris Greater Metropolis. The Territorial Coherence Plan envisions an attractive, resilient metropolitan area and a better quality of life for its inhabitants, in part by reducing territorial inequalities. It seeks to co-ordinate housing, transport, environmental and ecological issues. It advocates denser urban environments, better transport networks and the integration of risk management into all regional development projects (the built environment, economic activities, urbanisation, etc.).
Urban planning policies guided by economic development documents and water resource management are still not sufficiently aligned to maintain water levels and tackle pollution. For example, between 2011 and 2017, more than 20 000 hectares of wetland disappeared due to urbanisation in the Seine–Normandy basin (Agence de l'eau Seine Normandie, 2023[37]). Some cities are however pioneering the integration of water issues into their urban planning policies. The City of Paris, for example, included tackling soil sealing, recycling rainwater for watering, and better retention of rainwater as objectives under its local urban development plan in 2018.
However, the Seine–Normandy water agency has identified a number of promising avenues for improving how water preservation is taken into account. Firstly, according to the Seine–Normandy water agency, one of the challenges for integrating the objectives of the Seine–Normandy basin Master Plan for Water Development and Management (SDAGE) is the lack of data on the resources available to do so. A platform offering guidance on the SDAGE objectives is now publicly available to support local authorities. The platform also has various resources, such as examples of local urban development plans incorporating these issues. Moreover, although the law requires local urban development plans to comply with the SDAGE, it is primarily a guidance document that does not impose any prescriptive rules and therefore places little burden on local authorities. Conversely, at the sub-basin level, it is possible to draw up water development and management plans that transpose SDAGE objectives into operational objectives and these plans may have regulatory status. Deploying such plans at the local level is therefore a promising way to encourage local authorities to revise their local urban development plans.
Agriculture
The agricultural sector is a key actor in the region's resilience strategy. As the second-largest consumer of water in the region, agriculture is both highly vulnerable to drought risks and a source of pressure on existing resources. It is therefore logical that the sector should incorporate resource management principles and consideration of the risk of scarcity into its practices. Representatives of the agricultural sector regularly take part in decision-making via basin committees, the national water committee and local commissions, as well as other forums for consultation set up to manage water resources among users (e.g. Varenne on agriculture and climate change adaptation). Finally, the agricultural sector is responsible for polluting water resources, which jeopardises resource availability in the event of lower groundwater levels.
The agricultural sector is primarily guided by the European principles of the common agricultural policy (CAP) under the responsibility of the Ministry of Agriculture, which makes little provision for drought risks. Indeed, the European Court of Auditors conducted a study to assess the alignment of the CAP with the objectives of the Water Framework Directive (European Court of Auditors, 2021[38]). It turns out that the CAP does very little to take account of these objectives, and even encourages behaviours that run counter to efforts to protect water resources. For example, CAP payments subsidise crops that consume large volumes of water in water-stressed areas (e.g. potatoes grown using water from the Champigny aquifer (Aqui'Brie, 2023[39])). Furthermore, while financial support is available for environmental measures, the region's Chamber of Agriculture noted that this support is insufficient, as it covers only part of the costs of changing practices.
Through the European rural development programmes, regions are able to play a role in aligning water management and agricultural development objectives. They can do this by setting up a seven-year rural development programme to allocate funds from the European Agricultural Fund for Rural Development (EAFRD) to agricultural investments or to support practices that could impact water use. In the Centre-Val de Loire region, for example, regional investments are refused if they would lead to an increase in water abstraction on land in areas under water stress (European Court of Auditors, 2021[38]). In fact, the region can finance interventions not linked to surface area, such as flat-rate agri-environmental and climate measures, aid for plant and non-plant investments on farms, aid for setting up farmers, or risk management tools. To achieve this, the region must identify the environmental challenges facing its territory in its regional rural development programme and set out the areas in which agri-environmental and climate measures can be implemented. These measures influence both the quantity of water withdrawn and the pollution of water resources.
Although the Paris metropolitan area has an ambitious strategy for agriculture, it may prove insufficient to address drought challenges and may even accelerate the onset of water shortages. Indeed, the region has plans to promote regional and local agriculture (Région Ile-de-France, 2021[40]) and has established food sovereignty and economic development in the sector as priorities. The Paris metropolitan area’s authority supports practices and infrastructure that have a positive effect on soil water availability or that enable more restrained water use. For example, the region supports farmers to set up and diversify their practices or support the ecological transition and recognises water-related challenges to a certain extent (Région Ile-de-France, 2021[40]). For example, the region allocates EUR 1 million a year to agricultural innovation, for measures such as water conservation through smart irrigation sensors, or lower energy consumption by using weeding robots. Beyond these specific measures, the development of the agricultural sector in the region does not seem to take account of water resource scarcity. The regional plan now includes 66 specific measures under five challenges, none of which mention the increasing scarcity of water resources. Although the desire to diversify crops, encourage the re-emergence of vineyards and support fruit and vegetable growing are laudable objectives, the region does not assess the increased water requirements needed to achieve this plan, nor any accompanying measures to enable efficient water use. The Chamber of Agriculture meanwhile does not foresee any change in crop selection.
Energy
The decision to pursue electrification to meet the carbon neutrality targets set out for 2050 in France's energy and climate strategy could be vulnerable to droughts. Decarbonising energy requires an increase in the share of electricity in the energy mix and the use of renewable energies in proportions that will depend on the future of nuclear power in France (RTE, 2021[41]). The region plans to increase electrification by 35% overall by 2050, mainly through the electrification of transport, but also through the deployment of green hydrogen technologies and consumption in the industrial sector. This transition would be based either entirely on renewable energies or on a balance between renewable energies and nuclear power (from 13% to 50% nuclear). There could be even greater electrification, according to France's Energy Efficiency plan, which forecasts a 55% increase in electricity use by 2050 and a 40-50% reduction in overall energy consumption by the same date (France, 2022[42]).
Climate change-induced droughts may increase the vulnerability of the energy sector, given that there is likely to be greater dependence on nuclear power and hydropower generation. According to RTE, existing nuclear power plants located on river banks will be more regularly affected by periods of high heat and drought, with significant impacts on electrical power supply (RTE, 2021[41]). RTE mentions, for example, the role of cooling units, which will be required for riverside power plants. As the electricity grid covers the whole country, any issues with the grid due to droughts would have repercussions for the region. Moreover, it is not unlikely that electricity generation will be affected by drought, or that water will be unusable because it is too hot. For example, in 2022, hydropower generation was 20% lower than the 2014-19 average (RTE, 2022[43]). However, in the event of water scarcity, the role of dams could be reconsidered to satisfy other needs. In 2022, four riverside nuclear power plants were only able to continue operating, at reduced power, thanks to restrictions being waived (ASN, 2022[44]).
While local authorities have little room for manoeuvre when it comes to national energy security, their climate strategies are indirectly based on river resources, but they pay inconsistent attention to droughts risks. For example, the region is planning to develop clean mobility based on electric means of transport, to cope with increases in service sector jobs, population and new housing (Région Ile-de-France, 2013[45]). This increase in electricity consumption is being planned without assessing the risks that climate change poses to water resources and the national grid. Similarly, the City of Paris is planning an energy mix based entirely on renewable energies, which includes tripling the production of cooling networks and reducing consumption. The city's cooling networks currently draw water from the Seine (73% of sites are dependent on river resources). They could be increasingly affected by restrictions due to the temperature levels that may be reached during the summer period. According to the master plan for the Paris cooling system, the network is expected to deliver 1 000 GWh a year of energy by 2050, a 2.5-fold increase on the power currently delivered (Ville de Paris, 2019[46]). However, according to Fraîcheur de Paris, the development strategy for the network is increasingly based on systems that will not be dependent on the temperature of the Seine, and therefore more resilient to water scarcity.
Conclusion
Adaptation strategies, resilience plans, or climate policies developed at all administrative levels converge toward reducing vulnerability to the risk of water scarcity caused by droughts. However, the lack of quantified medium- and long-term evaluations of water supply and demand makes it difficult to effectively adapt current strategies. Recent studies from Explore 2 enhance understanding of future water supply, but precise frameworks for assessing demand are still missing. Lastly, a lack of coherence between climate, energy, agricultural, and urban policies could create new vulnerabilities. Better coordination of these policies at both national and local levels would be essential to strengthen resilience against the growing risk of water scarcity.
References
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