Nature-Based Solutions (NbS) are increasingly recognized as effective and sustainable approaches to address complex water-related challenges such as flood risk, biodiversity loss, and water quality degradation. By leveraging natural processes and ecosystem functions, NbS offer resilient, adaptive, and often cost-effective alternatives or complements to traditional grey infrastructure. In Northwest Europe, interest in NbS is growing, yet widespread implementation is hindered by institutional inertia, limited metrics for co-benefits, and a lack of standardized assessment methods.

This contribution discusses key challenges and opportunities for mainstreaming and upscaling NbS, drawing on a broad base of literature and practical experiences. It emphasizes the need for clear definitions, objective comparison frameworks, and stronger integration of co-benefit valuation into decision-making processes. Tools such as the IUCN Global Standard for NbS offer valuable guidance, yet often require adaptation for specific regional and project contexts.

Insights from the EU-INTERREG ResiRiver project, which includes nine pilot sites across Belgium, France, Germany, Ireland, and the Netherlands, illustrate both the potential and practical limitations of implementing NbS across varying river types and governance settings. ResiRiver demonstrates how self-assessment tools, stakeholder engagement, and targeted communication strategies—such as policy briefs and virtual excursions—can support more effective adoption.

Achieving large-scale implementation of NbS requires a combination of technical innovation, institutional commitment, and knowledge exchange. Strengthening scientific evidence, improving outcome-based monitoring, and fostering international collaboration will be key to realizing the full potential of NbS in river basin management.

Channel patterns and river connectivity are widely recognized to be an integral descriptive parameter for the geomorphic behaviour and ecohydrological properties of rivers. They are sensitively affected by climate and land-use changes and, in turn, can indicate the habitat suitability for the aquatic fauna, i.a. expressed by the diversity of channel width, flow velocity and depositional regimes. Both, habitat potential and the overall river connectivity are additionally influenced by barriers such as weirs and dams, at least since Medieval times. Here we present the results of a multi-temporal study investigating river morphology, river connectivity and floodplain land use in the Mulde River system. The study is motivated by the local extinction of the Atlantic Salmon (Salmo salar) within the last two centuries and low-success reintroduction endeavours. In order to test for a relation to water body structures, we make use of old maps (‘Sächsische Meilenblätter’, 1780-1821; ‘Von Deckersche Quadratmeilenblätter’, 1816-1821) to pinpoint (i) historical barriers and (ii) historical floodplain land use as a pollution proxy that may have affected migratory fish populations. Furthermore, we (iii) evaluate anthropogenic changes in channel patterns assuming that these also influence salmon habitat suitability. Preliminary results point to a negative relation between an increasing number of cumulative barriers, increased floodplain land use and the occurrence of salmon populations during the past. Sinuous and meandering channel patterns correspond with higher probabilities of salmon occurrence.

Ostracoda (Crustacea) are widely used and approved proxies for lacustrine palaeoenvironments, but are rarely applied for characterising river sediments. Their densities are generally lower in rivers and overbank sediments, the latter often show dissolution of the calcitic ostracod shells. We think, however, that ostracods have a much higher potential for palaeoecological analysis of river sediments, especially when combined with molluscs, but this needs additional research. For further exploring their potential, we analysed recent ostracod associations from several river systems in Germany: The Saale and its tributaries around Jena (37 samples), streams in the Thuringian Forest (26), as well as two smaller rivers in southwestern Germany; Echaz and Eger (18). Almost all samples contained ostracods, most of them in high numbers, allowing detailed statistical analyses. We found 32 ostracod species in total. Most abundant are Candona candida, Cavernocypris subterranea, Cypria ophthalmica, Eucypris pigra, Ilyocypris inermis, I. bradyi, Limnocythere inopinata Prionocypris zenkeri, Psychrodromus olivaceus and Potamocypris zschockei. Water quality assessment based on recent or fossil associations, similar to the saprobia index, is possible and can be improved by combining ostracod with mollusc data. Water turbulence, phytal zones and non-permanent water cover are indicated. Special attention has to be paid to taphonomical effects, like transport, disarticulation, fragmentation, abrasion and dissolution.

Central European floodplains represent dynamic and sensitive socio-environmental hotspots significantly reshaped by human activity, particularly since the Early Middle Ages. This transformation fundamentally changed fluvial morphology, dynamics and sedimentary systems, raising questions about when and to what extent these landscapes can be understood as a ‘Fluvial Anthroposphere’. Our study focuses on the Wiesent River catchment in Northern Bavaria, Germany, as a case study to investigate the transition from naturally controlled to human-dominated floodplain systems.

Utilizing a multi-proxy approach including sedimentological, geophysical and chronostratigraphical analyses, we explore how direct (e.g. hydrotechnical installations) and indirect influences (e.g. catchment-wide soil erosion due to agriculture) have altered the fluvial morphology and sedimentary dynamics of the area. Detailed examination of floodplain architecture reveals thick overbank deposits and shifts in sediment dynamics that serve as proxies for anthropogenic activity. Optically stimulated luminescence (OSL) dating allowing us to link increases in sedimentation rates directly to the intensification of human activities within the catchment.

Sedimentation patterns along the Wiesent River correlate well with the Aufsess River sub-catchment (Fuchs et al. 2010, 2011). OSL ages show elevated sedimentation rates during the Migration Period (375-500 CE) and Early Middle Ages (500-1000 CE). Interestingly, while sedimentation was high, substantial human influence, like deforestation appears more prominent from the High Middle Ages on (1000 CE onwards). This temporal disconnection highlights the inherent time lag in the sediment cascade model, suggesting material eroded during the High Middle Ages may still be moving through the sediment cascade system, yet to be deposited in floodplains.

As part of the project “The River Weschnitz Fluvioscape and its Interaction with the Lorsch Abbey”, a focal point is an artificial fish pond situated within the natural floodplain, used from 1474-1718/20. Located south of Lorsch in the present-day Hessian Ried, the pond—known as Lake Lorsch—is notable not only for its size, nearly four square kilometers, but also for the minimal construction required for its creation and maintenance. As Henselowsky et al. (2025) demonstrate, favorable environmental conditions—a high groundwater table, sedimentological sealing, and a location below the receiving water body, the River Weschnitz—enabled the project with little structural intervention.

Later anthropogenic modifications—particularly post-use terraforming—have obscured original features such as inflow and outflow channels, hatching ponds, and bank reinforcements. The initial phase of this study therefore focuses on identifying and isolating these later impacts, especially dense drainage networks and current turf and agricultural use, to better reconstruct the late medieval fluvial landscape.

Geophysical methods (ERT, EMI and core analysis) have confirmed the presence of structures derived from historical cartography and archival documentation. Nonetheless, sedimentological evidence is limited: lacustrine horizons are absent, phosphorus levels only slightly elevated, and fine-grained fluvial deposits minimal. This reflects the lake’s unique operational history; archival records show it was periodically and deliberately drained, sometimes remaining dry for months or years. While intended to boost nutrient availability and fish productivity, this practice prevented the long term development of lacustrine soils and stratigraphy in general.