The hydrologic regime of a river is one of the factors determining its ecological status. This paper tries to indicate the present hydrologic stress occurring across European rivers on the basis of model integration. This results in a pan-European assessment at the resolution of the functional elementary catchment (FEC), based on simulated daily time-series of river flows from the model PCR-GLOBWB. To estimate proxies of the present hydrologic stress, two datasets of river flow were simulated under the same climate, one from a hypothetic least disturbed condition scenario and the second from the anthropogenic scenario with the actual water management occurring. Indicators describing the rivers’ hydrologic regime were calculated with the indicators of hydrologic alteration (IHA) software package and the river total mean flow and the relative baseflow magnitude over the total flow were used to express the deviations between the two scenarios as proxy metrics of rivers’ hydrologic alteration or hydrologic stress. The alteration results on Europe’s FEC-level background showed that Southern Europe is more hydrologically stressed than the rest of Europe, with greater potential for hydrology to be clearly associated with river segments of unreached good ecological status and high basin management needs.

Five years after its establishment (2016), the LTER-Greece network outlines its vision, aims, objectives and its achievements through a series of case studies. The network consists of eight observatories, focusing on innovative research topics, aiming to be both cooperative and complementary, while currently being in the process of expanding. LTER-Greece acknowledges the complexity of ecosystems and the fact that effective management of natural resources may only be achieved by addressing every sector of a nexus system in order to understand inter-dependencies, thus accounting for solutions that promote resilience. Hence, LTER-Greece focuses on the holistic study of the water-environment-ecosystem-food-energy-society nexus, in order to face environmental and socio-ecological challenges at local and global scales, particularly climate change, biodiversity loss, pollution, natural disasters and unsustainable water and land management. Framed around five research pillars, monitoring and research targets nine research hypotheses related to climate change, environmental management, socio-ecology and economics, biodiversity and environmental process dynamics. As environmental monitoring and related research and conservation in Greece face critical shortcomings, LTER-Greece envisages confronting these gaps and contributing with interdisciplinary solutions to the current and upcoming complex environmental challenges.

A Multi-criteria Decision Aid (MCDA) framework based on the combination of Multi-Attribute Utility Theory (MAVT/MAUT) with the Weights Assessment through Prioritization method (WAP) is proposed for decision problems related to agricultural water management in the context of water-energy-land-food (WELF) nexus. The implementation of the framework supports a Decision Maker (DM) to quantify his/her preferences in a structured and rational way, in order to select the best alternative for agricultural water management. Through the use of the Multicriteria Interactive Intelligence Decision Aiding System (MIIDAS), marginal utilities functions for all the criteria are constructed. The criteria are grouped in points of view, which may refer to individual nexus elements and costs for investments or agricultural inputs. The WAP software assists the DM to assess the relative importance of the criteria and estimate their weights.

Research Infrastructures (RIs) and Observatories (Obs) are essential to the advancement of environmental and water sciences as they offer facilities, services, and data that foster innovative and high-quality research. However, their broader use is often prevented by fragmentation, limited visibility, and complex access mechanisms. Within the European Water4All Partnership, a comprehensive and continuously updated repository of water-related RIs and Obs is being developed to enhance connectivity, accessibility, and use across Europe and beyond. The repository offers a structured and well-categorized overview of water-related RIs and Obs, including information on facilities, data and services provided, highlighting their remote data access capabilities, capacity for interconnections, and policy support, thereby improving visibility, interoperability, and identification of needs and gaps within the European water sector. By linking data producers, researchers, academics, policy-decision makers and stakeholders, it supports evidence-based decision-making, fosters capacity building, and facilitates cross-domain research while contributing to European and global water initiatives aligned with EU policies, UN Sustainable Development Goals (SDGs), and key water priorities, highlighting its added value for the water Research and Innovation (R&I) sector.