Ecohydrological Pathways of Water Quality Under Climate Change: Nature-Based Solutions for Pollutant Flux Regulation

Climate change is steadily reshaping hydrological regimes, and one of its clearest consequences is the growing disruption of the biogeochemical pathways that govern water quality across river basins. More frequent high-intensity rainfall events, prolonged dry spells, and shifts in seasonal runoff patterns are altering the timing and magnitude of nutrient, organic matter, sediment, and contaminant fluxes. These pulses of material often originate from short-lived episodes of enhanced connectivity between soils, groundwater, and surface waters, making water-quality responses more variable and harder to anticipate than in previous decades. This review describes the ecohydrological mechanisms underlying these changes, focusing on threshold behaviors, the functioning of transitional zones such as riparian corridors and floodplains, and the cumulative effects of legacy pollution. We also discuss the capacity of nature-based solutions (NbS) to buffer climatic pressures. Although NbS can improve retention and moderate peak flows, their performance proves highly sensitive to hydrological variability and landscape context. In the final part, we describe tools that can strengthen adaptive water-quality management, including high-frequency monitoring, event-focused early-warning systems, and modeling approaches that integrate hydrology with biogeochemical processing. This article addresses ecohydrological pathways for water quality under climate change and presents nature-based solutions for regulating pollutant flows within a general framework. Data from North America and Europe, among other areas, are used as primary examples. However, it is important to remember that the issues and proposed solutions vary depending on landscape conditions and climatic zones, which vary across the globe. This article provides an overview of the most common solutions.