| To understand coupled hydrological and carbon dynamics in heterogeneous, snowdrift-dominated headwater catchments, we determine stream water and dissolved organic carbon (DOC) sources and fluxes from hydrometric and hydrochemical signals of soil water, saprolite water, and groundwater at the Reynolds Creek Critical Zone Observatory, Idaho, USA. We interpret flowpaths during the snowmelt period and summer drying using end-member mixing analysis in light of inferred subsurface structure from geophysical transects. Our findings indicate: (1) rapid loss of soil water connectivity with groundwater, and (2) an unusually rapid and important groundwater flowpath along the soil/saprolite boundary. Previously stored soil water appears to be displaced into the saprolite and groundwater which source most DOC and integrate soil water across the catchment. That this catchment does not follow the expected
“flushing” model indicates a need for more detailed analysis of water sourcing in carbon export studies.
Keywords:
Dissolved organic carbon, DOC, soil organic carbon, SOC, hydrologic connectivity, soil water, ground water, snowdrifts, snow, infiltration, headwaters, dryland ecosystems, arid, desert, Idaho, Owyhee, Reynolds Creek, Critical Zone Observatory, CZO |