Europe's lake monitoring methods reveal major blind spots in water management
A comprehensive review of 13 European lake assessment systems shows that regulators can measure water flow changes and shoreline habitat damage—but have few tools to track groundwater connections, a critical factor for ecosystem health. The gap matters: water utilities, agricultural operators, and environmental regulators lack consistent data to make informed restoration and management decisions.
Originaltitel: Inventory of metrics for characterizing the hydromorphology and defining the ecological status of European lakes
Hydromorphological conditions are among the key determinants of the composition and abundance of biological assemblages in lakes. Consequently, hydromorphological alterations can significantly affect aquatic biodiversity and ecological status of lake ecosystems. Internationally, various methods have been developed to monitor and assess hydrological and morphological status, with particularly comprehensive efforts in Europe under the Water Framework Directive (WFD). In this study, we compiled and reviewed hydrological and morphological metrics included in 13 assessment methods currently used in Europe to assess lake hydromorphological conditions. These methods are applicable to both natural and man-made lakes and are designed to support the implementation of the WFD. We categorized the metrics by spatial scale, affected processes, and data requirements, to inform a more strategic selection of metrics and improve their alignment with lake management and restoration strategies. Of the metrics reviewed, those that refer to changes in water flows and littoral habitat quality are best described. In contrast, changes in the hydrological connection between the lake and groundwater are rarely assessed. Ongoing methodological advancements and emerging technologies, particularly in remote sensing, are expected to improve the accuracy and efficiency of hydromorphological alteration assessments in lakes. Future research needs are highlighted to address knowledge gaps regarding how climate change affects the hydrological and morphological characteristics of lakes, and, in particular to distinguish anthropogenic impacts on lake ecosystems from large-scale processes. A clearer understanding of these dynamics is essential for developing effective lake restoration strategies in the face of climate change. • In Europe, the WFD has stimulated research for characterizing lake hydromorphology. • National European experts were surveyed to identify all metrics currently in use. • Water flow and littoral habitat quality changes are the best-characterized parameters. • Changes in the connection between lake and groundwater are rarely assessed. • Methodological progress will improve these methods in the context of climate change.