Local vs. Regional Groundwater Flow Delineation from Stable Isotopes at Western North America Springs

Abraham E Springer, Elizabeth M. Boldt, Katie M. Junghans

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

The recharge location for many springs is unknown because they can be sourced from proximal, shallow, atmospheric sources or long-traveled, deep, regional aquifers. The stable isotope (18O and 2H) geochemistry of springs water can provide cost-effective indications of relative flow path distance without the expense of drilling boreholes, conducting geophysical studies, or building groundwater flow models. Locally sourced springs generally have an isotopic signature similar to local precipitation for that region and elevation. Springs with a very different isotopic composition than local meteoric inputs likely have non-local recharge, representing a regional source. We tested this local vs. regional flow derived hypothesis with data from a new, large springs isotopic database from studies across Western North America in Arizona, Nevada, and Alberta. The combination of location-specific precipitation data with stable isotopic groundwater data provides an effective method for flow path determination at springs. We found springs in Arizona issue from a mix of regional and local recharge sources. These springs have a weak elevation trend across 1588m of elevation where higher elevation springs are only slightly more depleted than low elevation springs with a δ18O variation of 5.9‰. Springs sampled in Nevada showed a strong elevation-isotope relationship with high-elevation sites discharging depleted waters and lower elevation springs issuing enriched waters; only a 2.6‰ difference exists in 18O values over an elevation range of more than 1500m. Alberta's springs are mostly sourced from local flow systems and show a moderate elevation trend of 1200m, but the largest range in δ18O, 7.1‰. Groundwater

Original languageEnglish (US)
JournalGroundwater
DOIs
StateAccepted/In press - 2016

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ASJC Scopus subject areas

  • Water Science and Technology
  • Computers in Earth Sciences

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