Napa River Watershed, U.S.A. soil leachate and surface water sulfate sulfur isotopes and concentrations

Sulfur (S) is widely used in agriculture, yet little is known about its fates and consequences within upland, mixed land-use land-cover watersheds. This dataset includes samples collected throughout the Napa River Watershed, California, U.S.A., where high S applications to vineyard agriculture are common. Sample collection focused on tracing the agricultural S “fingerprint” —or the combined S stable isotope composition and concentration of sulfate—through the Watershed. We collected samples during California wet seasons (December – April) over three years (2017-2020). Samples included vineyard agriculture and non-agricultural (primarily forest, grassland, and shrubland) soil water, culvert outflows, tributaries to the Napa River, and Napa River surface water. The data table includes water sample sulfate concentrations and sulfate-S stable isotope measurements as well as the stable isotope composition of S fungicide samples.