SURENEXUS concludes with a highly positive final evaluation and a new AI tool for WEFE Nexus assessment

The PRIMA Foundation congratulated the consortium during the final evaluation meeting held on 30 January 2026. Coordinated by the UNESCO Chair on Sustainability at the Universitat Politècnica de Catalunya (UPC), SURENEXUS concludes after three and a half years with the AI WEFE Nexus Tool and five Mediterranean demonstration cases. The tool provides a traceable framework for assessing water, energy, food and ecosystem trade-offs and, for agricultural applications, integrates FAO-based evapotranspiration calculations to derive net irrigation requirement (NIR) and gross irrigation requirement (GIR).

On 30 January 2026, the SURENEXUS project held its final evaluation meeting, organised by the PRIMA Foundation. After three and a half years of work, the project coordinator and the leaders of the eight work packages presented the final results to the programme office and the appointed experts. The evaluation concluded with a highly positive assessment and explicit congratulations to the consortium, recognising both the scientific quality of the results and the effectiveness of project management and coordination.

The AI WEFE Nexus Tool: making Nexus trade-offs traceable

At the centre of SURENEXUS is the AI WEFE Nexus Tool, the project's principal methodological and technological development. It combines four components: a formal conceptual model in SDL, an Assumptions Document (ADoc) co-produced with local stakeholders, the SDLPS simulation engine and the NECADA digital twin. Its artificial intelligence is symbolic and knowledge-based, with human oversight built into the process, so model outputs and recommendations can be traced back to the rules, constraints, data and assumptions that produced them.

A distinctive feature of the model is its FAO-based irrigation-water module. Rather than treating irrigation demand as a fixed external input, the AI WEFE Nexus Tool calculates crop evapotranspiration following FAO methodology and uses it to derive NIR and GIR. This links climate and crop water demand directly to irrigation performance and allows alternative management strategies to be compared on a common biophysical basis before their implications for energy use, agricultural production, costs and environmental performance are assessed. This module is particularly important for the Tunisia and Morocco demo sites.

Within NECADA, the Compensation Block compares conventional, nature-based and bioeconomy solutions through Pareto screening and stakeholder-weighted multi-criteria analysis, translating the results into harmonised KPIs, composite indices and heatmaps. Development of the common model required 45 dedicated technical meetings and 115 hours of joint work between modelling teams and demo-site leaders. Over the course of the project, the tool advanced from TRL 7 to TRL 8, moving from a validated system prototype towards a more operational and transferable decision-support environment.

Five Mediterranean demonstration cases, one shared Nexus framework

In the Penedès region (Catalonia), the Codorníu demo site assessed vertical-flow constructed wetlands using recycled cork granulate both as biofilm support and as a carbon source for denitrification. Among the eight configurations tested, the aerated cork system achieved nitrate removal of around 95%, compared with 40–45% in gravel-based configurations, with an energy demand of 84–93 kWh per month. When powered by photovoltaics, associated emissions are estimated at 20–35 kg CO₂e per month. The approach enables treated water reuse within the winery while valorising cork, a low-value local by-product, as a treatment medium.

On the island of Tinos in Greece, SURENEXUS tested two complementary solutions. At Agios Fokas, a solar evaporation–condensation desalination unit produces around 6 m³ of freshwater per month (72 m³ per year) with virtually no operational energy demand and fully renewable input. Compared with the conventional reverse-osmosis benchmark used in the project, it delivers 16% lower emissions, avoids 3–4 kWh/m³ of fossil-based electricity, recovers around 2.5 t of salt per year.

At Potamia, the Tinos Ecolodge served as a living laboratory for off-grid sustainable ecotourism: rainwater harvesting supplies around 10 m³ per month with zero operational energy use and emissions, rising to around 20 m³ when combined with a well. Its olive-tree agroforestry system with legumes and grasses achieved a composite WEFE index of roughly 2,700 units per month per hectare.

At Bir Ami, in Tataouine, southern Tunisia, SURENEXUS assessed water-efficient irrigation for olive production under severe aridity, groundwater pressure and high evaporative demand. The subsurface configuration reduced annual GIR by about 39%, mainly through lower direct soil evaporation and better retention of moisture in the root zone. The strongest relative water savings occurred during June–August, while the lower GIR also reduces pumping requirements and associated energy demand. Importantly, the AI WEFE analysis made the Water–Food trade-off explicit: the normalised food-performance indicator decreased from 1.00 for the drip scenarios to 0.87 for subsurface irrigation, but the equal-weight composite WEFE score increased from 0.33 to 0.55 because of the substantial gains in water efficiency.

At INRA's Digital Citrus demo site in Kenitra, Morocco, precision irrigation, mulching and solar pumping were evaluated across four hectares of citrus in the Gharb region. Here, the same FAO-based evapotranspiration and irrigation-requirement module was used to quantify NIR and GIR under alternative management scenarios. Simulations indicated a 43% reduction in annual gross irrigation requirement — from 496.5 to 282.3 mm — alongside a reduction in pumping energy from 142 to 88 kWh per month. Depending on the mandarin or orange variety, water productivity increased by a factor of 1.74 to 4.76.

Fifteen institutions, seven countries, a shared way of working

SURENEXUS — Ensuring fair NEXUS transition for climate change adaptation and sustainable development implementation, based on coupled Nature-based Systems and Bioeconomy — ran from April 2022 to September 2025 under the PRIMA 2021 call. It brought together fifteen institutions from seven countries, with an executed budget of close to €4.7 million.

Coordination was one of the project's defining strengths. Over 42 months, the consortium held four face-to-face meetings — in Barcelona, Athens, Rabat and Cairo —. The project's Stakeholder Platform ultimately reached 250 institutions across the Mediterranean basin, creating a broad community for testing, discussing and transferring the Nexus approach.

The project ends, the approach continues

With SURENEXUS formally concluded, the UNESCO Chair on Sustainability at UPC is now working to extend the approach to transboundary settings. The initiative was presented at the Ninth Meeting of the WEFE Nexus Task Force under the UNECE Water Convention (Geneva, June 2025) and at the XXVI Conference of Ibero-American Water Directorates, CODIA (Santiago de Chile, October 2025), where delegations from more than ten countries expressed interest in co-developing the next phase of an AI tool for Nexus cooperation.