Hydrochemistry of Springs and Groundwaters from the Sevilleta National Wildlife Refuge, 2007-2009

The Rio Grande is well-studied as a regionally important water source, but the small, poorly characterized springs that surface within the Rio Grande rift are also a vital resource. Several of these springs have water chemistries that suggest a mixing of larger volume meteoric recharge with small volume, deeply-sourced fluids. It has been hypothesized that deep-seated faults within the rift provide conduits for the ascent of deeply-derived fluids, while others have proposed that upwelling sedimentary basin brines represent a significant salinity input to the modern river. This study provided the first hydrochemical data on a comprehensive suite of springs and wells in the Sevilleta National Wildlife Refuge, and tested and refined existing models for water quality in the rift using hydrochemistry, microbial characterization, and geochemical modeling along a series of transects.