CEAB-CSIC is developing NEREIDA, a project that creates and uses digital twins (virtual replicas of rivers, reservoirs and coastal areas) to anticipate changes in water quantity and quality and support water resources planning and management, currently in the Ter and Tordera river basins. The project is funded by the Catalan Water Agency (ACA), which contributes through project oversight, data provision and technical guidance. Marking the project’s first year of implementation, the team has made the first operational tools for streamflow forecasting and saltwater intrusion prediction publicly available, together with the datasets they generate.
Water management in Catalonia faces growing challenges: more frequent and intense droughts, extreme temperature events, pollution and the loss of aquatic biodiversity. In this context, the Blanes Centre for Advanced Studies of the Spanish National Research Council (CEAB-CSIC), with the support and oversight of the Catalan Water Agency, launched the NEREIDA project in July 2025 to place advanced scientific forecasting at the service of water management in Catalonia.
NEREIDA develops digital twins (virtual replicas of aquatic ecosystems) for the Ter and Tordera river basins, integrating hydrological, climate and water-quality models. Through the use of predictive modelling, high-performance computing and remote sensing, the project aims to provide reliable forecasts on seasonal timescales (up to seven months ahead) and long-term timescales (between one and ten years), strengthening the capacity to anticipate the impacts of climate change on water resources.
The project’s main innovation lies in its focus on forecasting timescales that have received relatively little attention in the water sector, despite being among the most useful for management purposes because they enable medium and long-term planning. This information is highly relevant for water management and will provide a practical tool that can subsequently be used by the Catalan Water Agency and other organisations involved in water-resource management.
First results now openly available
Although still in the first year of this three-year project, the team has already made the first preliminary operational tools publicly available. Through the project page on the CEAB website (https://www.ceab.csic.es/projectes-recerca/nereida/), users can access:
- Seasonal forecasts of streamflow (Ter and Tordera) and reservoir storage volumes (Ter): projections for the next seven months in the Ter and Tordera basins, including the storage volumes of the Sau and Susqueda reservoirs (https://nereidaca.github.io/seasonal_hydro/).
- Monitoring and modelling of saltwater intrusion: a data viewer (https://nereidaca.github.io/saltwater_intrusion_data/) and a predictive model (https://nereidaca.github.io/saltwater_ML/) for the mouths of the Ter and Tordera rivers, which are crucial for managing impacts on agriculture.
These tools are currently under development and continuous improvement in close collaboration with water-management practitioners and experts.
A project built with and for water managers
A project built with and for water managersOne of NEREIDA’s distinctive features is its co-creation approach: the tools are being designed jointly with technical staff from the ACA and other institutions and companies involved in water management, ensuring that they respond to real operational needs. Two co-development workshops have already been held, during which stakeholder needs and priority case studies were identified. A third workshop will take place shortly and will incorporate two new topics that emerged from this collaborative process: modelling the salinisation of coastal aquifers and developing quality metrics for coastal ecosystems.
The project includes a total of six co-development workshops over its three-year duration and will conclude with a roadmap for scaling up the methodology to all river basins within Catalonia’s Internal River Basin District.
Rafael Marcé, Senior Scientist at CEAB-CSIC, explains: “NEREIDA represents an important step towards a water-management model in Catalonia based on anticipation rather than reaction. The tools we are building will enable the ACA and other stakeholders involved in the water cycle to address increasingly complex climate scenarios, including prolonged droughts, with forecasting horizons beyond those currently available, making better planning possible.”
About the project
NEREIDA (Digital twins for predicting and managing water quality and shoreline dynamics in Catalonia’s internal river basins) (https://www.ceab.csic.es/projectes-recerca/nereida/) is an applied research project running from July 2025 to June 2028.
The project has received €325,627 in funding through a grant from the Catalan Water Agency under its R&D&I funding programme (Resolution ACC/1362/2024).
The principal investigators are Rafael Marcé and Jordi Pagès Fauria, both from CEAB-CSIC, with the participation of researcher Daniel Mercado.
