About

Project background and Objectives

Water scarcity, water quality degradation and the loss of freshwater biodiversity are critical environmental challenges worldwide, which have primarily been driven by a significant increase in water withdrawals during the last century. In the coming decades, climate and societal changes are projected to further exacerbate these challenges in many regions around the world. As such, defining a safe operating space (SOS) for water resources in a changing climate and society is urgently needed to ensure a sufficient and reliable supply of water of a quality acceptable for human activity and natural ecosystems. Furthermore, it is one of the necessary conditions for achieving globally the Sustainable Development Goals (SDGs) by 2030, and in Europe for achieving in addition the objectives of the European Green Deal, the Biodiversity strategy for 2030, and those of the different European water policies including the Water Framework, Floods, Nitrates and Drinking Water Directives. However, defining the SOS for the entire water resources system at spatial scales relevant to decision-making and its projections into the future requires going beyond state-of-the-art water system modelling toward a holistic and participatory assessment framework that includes data gathering, integrated modelling, and working with relevant stakeholders.

SOS-Water aims to create the foundation for this framework, by co-creating future scenarios and management pathways with stakeholders in five case studies in Europe and abroad. It will advance water system models and link them with impact models of ecosystem services and biodiversity, to create a novel integrated water modelling system. This integrated water modelling system will be benchmarked against a wide range of state-of-the-art Earth observations and will be used to calculate selected indicators covering all dimensions of water resources systems, to ultimately design a multi-dimensional SOS of policies and water management pathways evaluated across a broad set of scenarios. The results of SOS-Water will help improving the understanding of water resources availability and streamline water planning and management at local to regional levels and beyond, such that the allocation of water among societies, economies, and ecosystems will be economically efficient, socially fair, and resilient to shocks.

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The Challenge

Global water systems are under unprecedented stress due to rising demands from agriculture, energy, and urban development, compounded by climate change and poor water governance. Water withdrawals have surged sixfold over the last century—nearly double the pace of population growth—leading to shrinking water reserves, degraded ecosystems, and increasing conflicts over water use. 

  

Climate change intensifies these problems by triggering more frequent and severe droughts, floods, and disruptions in water quality and availability. Existing models and policies often fail to address the full complexity of water systems, overlooking essential ecological, social, and economic interconnections. 

  

The SOS-Water project addresses this urgent challenge by developing a groundbreaking framework to define a Safe Operating Space (SOS) for water. This holistic approach integrates cutting-edge models, Earth observations, and stakeholder input to guide sustainable and resilient water management across regions. It moves beyond fragmented assessments to support policy and planning that balance human needs, ecosystem protection, and climate resilience. 

Methodology and conceptual framework

To achieve its objective, SOS-Water builds on a dual-track research approach—two complementary “rails” (first research line)—linked through essential connecting “steps” (second research line) to create a fully integrated and participatory water system Safe Operating Space (SOS) framework (see Figure on the left). 

The Two Rails: Science and Stakeholders 

The foundation of the SOS-Water methodology is built on two core components: 

  • An Integrated Water Modelling System (IWMS): advanced scientific models that simulate the full water cycle, water use, ecosystem needs, and socio-economic demands at high spatial resolution. 
  • An Inclusive Participatory Process: deep engagement with local stakeholders to co-develop water values, scenarios, and management pathways tailored to specific regional challenges. 

These two rails are designed to run in parallel and in coordination, ensuring that scientific advancements are not only technically robust but also locally relevant and implementable. 

The Two Connecting Steps: Earth Observation and Indicators 

To climb the “ladder” toward a holistic SOS framework, SOS-Water connects its two rails through: 

  • Earth Observation (EO): collecting, integrating, and interpreting satellite and in-situ data to monitor water quantity, quality, and ecosystem conditions. 
  • Indicators and Thresholds: developing a unified set of multi-dimensional indicators—covering environmental, social, and economic aspects—that define the boundaries of a safe operating space for water systems. 

From Framework to Action 

By linking participatory scenario building with state-of-the-art modelling and EO-based indicators, SOS-Water will design and assess the water system SOS in five diverse case studies across Europe and the Mekong region. This iterative and scalable framework will serve as a blueprint for sustainable, inclusive, and resilient water management in river basins worldwide. 

The Output

Project Outputs 

The SOS-Water project will deliver a set of practical and scientific outputs that support better decision-making for sustainable water management at local, regional, and continental scales. These include: 

  1. An Operational Water System SOS Framework

A holistic assessment framework that defines the Safe Operating Space (SOS) for water systems, integrating water quantity, quality, ecosystem needs, and human demands. The framework will be: 

  • Actionable – applicable in real-world planning and management 
  • Scalable – from local river basins to continental levels 
  • Transferable – adaptable to diverse climatic, social, and ecological contexts 

  

  1. Integrated Water Modelling System (IWMS)
  • A new generation of advanced models that: 
  • Simulate hydrology, water use, biodiversity, and socio-economic impacts 
  • Operate at high spatial resolution (1 km) 
  • Provide insights into climate risks, water scarcity, droughts, and floods 

  

  1. Participatory Scenarios and Management Pathways

Co-developed with local stakeholders in five case studies, these outputs include: 

  • Water values and priorities identified by communities 
  • Scenario narratives reflecting local visions and global challenges 
  • Management pathways tailored to basin-specific needs 

  

  1. A Hierarchical System of Indicators and Meta-Indicators

A scientifically validated set of water indicators to: 

  • Measure the status and performance of water systems 
  • Define thresholds and risks under various scenarios 
  • Enable multi-objective decision-making 

  

  1. Earth Observation Data Inventory and Tools

An extensive catalogue of EO datasets and tools that: 

  • Enhance monitoring of water availability, quality, and ecosystem health 
  • Improve the calibration and validation of water models 
  • Support early-warning and risk detection at multiple scales 

  

  1. Open-Source Data, Models, and Guidance
  • All models, tools, and datasets developed will follow open science and FAIR principles (Findable, Accessible, Interoperable, Reusable) 
  • Guidelines to replicate and scale the framework to new regions 
  • Educational and visual materials for wider public and stakeholder use 

Project Impact

The water system SOS assessment framework that will be developed by SOS-Water will contribute to advancing the water science by downscaling and operationalizing the concept of global freshwater SOS and making it relevant and informative at the regional and local scales at which water is managed. Moreover, the framework will be able to inform the design of water management pathways to address the ongoing and imminent water challenges, that maximize both the socio-economic and ecological value of water and are endorsed by stakeholders.
The water system SOS assessment framework will be implemented within five different case study regions based on an inclusive and iterative stakeholder process to enforce direct outcomes and foster long-term impact. However, SOS-Water pursues to provide guidelines and principles to enable its application elsewhere to ensure uptake outside SOS-Water and legacy beyond the project duration.

 

On a wider scale, the full adoption of the water system SOS assessment framework within the EU, regional and basin level policymaking will significantly contribute to inform the involved communities, companies, and decision-makers about the role of the holistic management of water resources within the climate change debate, planning for future infrastructure and the societal benefits of acting now rather than later.