Snapshot sampling of stable water isotopes can reveal spatial heterogeneity in storage, evaporative, and mixing processes of surface water systems. This sampling approach is particularly useful in wetland-rich catchments. These catchments often have high spatial heterogeneity in terms of landcover and surficial geology, and have complex scaling processes, where downstream processes are not simply a sum of upstream processes. Augusta Creek is a wetland-rich, mesoscale catchment located in southwestern Michigan. Previous studies have shown elevated concentrations of SO4 and NO3 downstream compared to the upstream subcatchments, suggesting greater contributions from older deep groundwater sources in downstream reaches. To validate this hypothesis, we conducted ~bi-weekly snapshot sampling of stream water isotopes across 28 sites along with precipitation sampling across 2 sites within the Augusta Creek catchment from September 2024 through September 2025 and calculated amplitude ratios of sine fits of precipitation and surface water as a proxy for water age. Preliminary results indicate water is generally younger in the headwaters but has high spatial variability in water age for catchments smaller than 25 km2. However, the relationship between subcatchment area and water age is different than the relationship between subcatchment area and SO4 and NO3 concentrations. These results suggest increases in SO4 and NO3 concentrations is not driven by the presence of deeper and slower flowpaths but is likely driven by differences in soil and aquifer chemistry between upstream and downstream reaches. These results highlight the value of snapshot isotopic sampling in characterizing heterogeneity in catchment storage and mixing processes.