Healthy freshwater ecosystems (streams, rivers, and lakes) sustain public health, economic vitality, and ecosystem integrity. The dissolved and particulate constituent concentrations and loads within these ecosystems are controlled by a wide array of factors such as the geomorphological, hydrological, biogeochemical, climatic and anthropogenic processes. The integrative nature of signals at larger spatial scales is still elusive. We call for submissions that showcase advances in the study of watershed biogeochemistry at large scales (national & regional), with a special focus on using large datasets (such as from monitoring or survey network) and innovative modeling (eg. machine learning) or statistical approaches. Studies that highlight novel datasets (high frequency data, remote sensing), models (WRTDS, SWAT, SPARROW), or other approaches (mass balance, hydrograph separation, isotope tracers) to address these focus areas are also welcome.