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The Valles Caldera is an ideal natural laboratory for testing multi-tracer hydrochemical models of geothermal fluid outflow and mixing in distal portions of geothermal systems. Springs with an endogenic component provide evidence of the plume, while the Jemez River provides a location for mixing of different end-member fluids. The models are of relevance for exploiting geothermal potential and understanding threats to water quality. The Valles Caldera is part of a hydrothermal system which has seen extensive study with focus on assessing geothermal potential. The outflow system, the Baca Plume, flows along the fault network in San Diego Canyon. Two pathways have been suggested for the plume, one discharging at Soda Dam and the other at Jemez springs. Questions remain about the extent of the plume and distal effects of the Valles Caldera, with current research suggesting a connection to springs across the Nacimiento Mountains. Geothermal groundwater components lead to degradation of water quality in the Jemez River, a snow melt dominated system, and associated alluvial aquifer; a problem for local stakeholders. With climate change forecasts predicting reduction in snow pack, the contributions to surface water from springs takes on greater significance. Our pilot studies and historical work have used major ion and gas chemistry, and stable isotopes to define the geothermal plume and highlight mixing of different end member fluids. Preliminary geochemical mixing models show that springs at Soda Dam and Jemez Springs do not fall along a simple binary continuum. The significant differences in hydrochemistry suggest complex fault-related flow-paths. [ABSTRACT FROM AUTHOR]