Integrating multiple geophysical methods to understand groundwater storage and discharge in tropical proglacial catchments

R. Glas, Laura K Lautz, J. McKenzie, Robert Moucha, B. Mark

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The Cordillera Blanca in Northwestern Peru is home to a quarter of the world's tropical glaciers, where hydrologic regimes are rapidly changing due to warming- induced glacier recession. Proglacial alpine meadows are storing a significant portion of annual basin discharge, and buffer dry season low flows as glaciers continue to lose their influence on the regional hydrologic cycle. We used integrated seismic (refraction, H/V passive seismic) and electrical (2D ERT and 1D soundings) in conjunction with borehole data to characterize the nature of proglacial talus aquifers in alpine meadows at elevations above 3500 masl. The meadow subsurface exhibits a transition from relatively slow (400-800 m/s) to fast (~2500 m/s) seismic p-wave velocity at depths of 4 to 8m, coinciding with the top of a composite layer of buried talus boulders, according to borehole data. Artesian pressure head in piezometers screened at the boulders indicate the presence of an aquifer confined by clay sediments. Resistivity profiles suggest that the upper most portions of the buried talus deposit are infilled with saturated clay, which dissipates with depth where sediments become more electrically resistive. Passive seismic and 1D electrical soundings suggest that total sediment thickness extends deeper than 20 m, allowing for first estimates of talus aquifer storage volumes and groundwater residence times. Based on the results from this study, we present a refined conceptual model of talus aquifers, from their formation to hydrologic function. Throughout the Cordillera Blanca, buried talus aquifers have the potential to store between 7 and 20% of annual basin discharge, which will allow for future predictions of dry season base flow for the region's principal river.

Original languageEnglish (US)
Title of host publication24th European Meeting of Environmental and Engineering Geophysics
PublisherEuropean Association of Geoscientists and Engineers, EAGE
ISBN (Electronic)9789462822634
DOIs
StatePublished - Jan 1 2019
Event24th European Meeting of Environmental and Engineering Geophysics - Porto, Portugal
Duration: Sep 9 2018Sep 13 2018

Other

Other24th European Meeting of Environmental and Engineering Geophysics
CountryPortugal
CityPorto
Period9/9/189/13/18

Fingerprint

talus
geophysical method
Aquifers
Catchments
Groundwater
Glaciers
catchment
groundwater
Sediments
aquifer
meadow
glacier
Boreholes
Clay
cordillera
dry season
borehole
Seismic waves
clay
sediment thickness

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Geochemistry and Petrology
  • Energy Engineering and Power Technology

Cite this

Glas, R., Lautz, L. K., McKenzie, J., Moucha, R., & Mark, B. (2019). Integrating multiple geophysical methods to understand groundwater storage and discharge in tropical proglacial catchments. In 24th European Meeting of Environmental and Engineering Geophysics European Association of Geoscientists and Engineers, EAGE. https://doi.org/10.3997/2214-4609.201802464

Integrating multiple geophysical methods to understand groundwater storage and discharge in tropical proglacial catchments. / Glas, R.; Lautz, Laura K; McKenzie, J.; Moucha, Robert; Mark, B.

24th European Meeting of Environmental and Engineering Geophysics. European Association of Geoscientists and Engineers, EAGE, 2019.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Glas, R, Lautz, LK, McKenzie, J, Moucha, R & Mark, B 2019, Integrating multiple geophysical methods to understand groundwater storage and discharge in tropical proglacial catchments. in 24th European Meeting of Environmental and Engineering Geophysics. European Association of Geoscientists and Engineers, EAGE, 24th European Meeting of Environmental and Engineering Geophysics, Porto, Portugal, 9/9/18. https://doi.org/10.3997/2214-4609.201802464
Glas R, Lautz LK, McKenzie J, Moucha R, Mark B. Integrating multiple geophysical methods to understand groundwater storage and discharge in tropical proglacial catchments. In 24th European Meeting of Environmental and Engineering Geophysics. European Association of Geoscientists and Engineers, EAGE. 2019 https://doi.org/10.3997/2214-4609.201802464
Glas, R. ; Lautz, Laura K ; McKenzie, J. ; Moucha, Robert ; Mark, B. / Integrating multiple geophysical methods to understand groundwater storage and discharge in tropical proglacial catchments. 24th European Meeting of Environmental and Engineering Geophysics. European Association of Geoscientists and Engineers, EAGE, 2019.
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