Répartition spatiale de la température ponctuelle d'une couche comme marqueur quantitatif de traçage d'un flux percolant

Translated title of the contribution: Scaling up point-in-space heat tracing of seepage flux using bed temperatures as a quantitative proxy

Laura K. Lautz, Rachel E. Ribaudo

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

It is challenging to quantify reach-scale surface-water-groundwater interactions, while maintaining the fine-scale spatial resolution required in hyporheic studies. One-dimensional heat-transport modeling was used to simulate streambed fluxes at discrete points using time-series temperature records. A predictive relationship was then developed between point-in-time streambed temperature and modeled flux rates. Flux was mapped at high spatial resolution by applying the predictive relationship to mapped streambed temperatures, which allowed for high-resolution quantification of flux by proxy. Inferred patterns of flux are consistent with morphology and yielded a net flux to a 30-m stream reach of 1.0 L s -1. Discharge of saline groundwater (5.7 g L -1 Cl -) allowed for comparison between the temperature proxy method and geochemical variability. Maximum upwelling locations (>35 cm day -1) were spatially coincident with areas of high conductance at the bed interface (5-25 mS cm -1). Differences between gross flux estimates from heat and geochemical methods are attributed to differences in the spatial extent over which estimates were derived and limited sensitivity of the temperature-as-proxy method. When bed temperatures are near their inherent limits (groundwater and stream-water temperatures) the flux magnitude can be underestimated. Caution must be used when determining gross, reach-scale fluxes from temperature-as-proxy methods when flux rates are outside the sensitivity limits.

Translated title of the contributionScaling up point-in-space heat tracing of seepage flux using bed temperatures as a quantitative proxy
Original languageFrench
Pages (from-to)1223-1238
Number of pages16
JournalHydrogeology Journal
Volume20
Issue number7
DOIs
StatePublished - Nov 1 2012

Keywords

  • Equipment/field techniques
  • Groundwater/surface-water relations
  • Heat transport
  • Hyporheic interaction
  • USA

ASJC Scopus subject areas

  • Water Science and Technology
  • Earth and Planetary Sciences (miscellaneous)

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