Main ongoing research 

With my current research, I focus on linking hydrological and biogeochemical processes in rapidly changing environments. To this end, my colleagues and I use a combination of various techniques from sampling of tracers in the field to numerical modeling and remote sensing.

Papers in the pipeline (in print, under review or in preparation; drafts available upon request):

Linking groundwater discharge and greenhouse gas evasion in alpine, sub-arctic catchments (Finse, Norway)

Fieldwork for this project takes place in Finse. This project is part of LATICE (Land-ATmosphere Interactions in Cold Environments).

The response of groundwater to changes in the snowpack (Sagehen Creek, California)

Data for this project comes from the Sagehen Creek Field Station in California (US). This project is funded by the Peder-Sather Grant Program

Integrating hydrology and biogeochemistry in a High-Arctic catchment (Ny-Ålesund, Svalbard)

Fieldwork for this project takes place in the High Arctic in Ny-Ålesund, Svalbard. This project is funded by an Arctic Field Grant of the Norwegian Research Council.

Working Group 1 Co-Chair of EU COST Action WATSON—WATer isotopeS in the critical zONe: from groundwater recharge to plant transpiration;

One of the key goals of WATSON is to create an extensive database of water isotopes from various water sources in Europe. 

Past research

During my PhD, I used a combination of novel tracer techniques and modeling to enhance our understanding of the interactions between streams and shallow groundwater and what implications these exchange processes have on biogeochemical cycling (such as denitrification). Besides my PhD, I was leading or was involved in several other projects. 

Key publications (for a complete list, please see my GoogleScholar profile):


This paper introduces a framework to estimate mean travel times of a groundwater fraction consisting of recently infiltrated river water. 

Keywords: mean travel times, mixing, novel tracer techniques, surface water-groundwater interactions

Citation: Popp, A.L., Pardo-Álvarez, Á., Schilling, O., Musy, S., Peel, M., Brunner, P., Purtschert, R., Hunkeler, D., Kipfer R. (2021) A framework for untangling transient groundwater mixing and travel times. Water Resources Research,

Selected as Editor’s Research Spotlight on Eos:


Here we describe the potential of mobile mass spectrometry to advance hydrological sciences. 

 Keywords: on-site gas analysis, environmental tracers

Citation: Popp, A.L.*, Manning, C.*, Knapp, J.L.A*. Rapid advances in mobile mass spectrometry enhance tracer hydrology and water management. Water Resources Research,

*shared first-authorship


This article presents a new way to quantify denitrification in groundwater with a high spatiotemporal resolution using portable mass-spectrometry. 

Keywords: denitrification, riparian groundwater, high-resolution measurements of dissolved gases, infiltration

Citation: Popp, A.L., Manning, C., Brennwald, S., Kipfer R. (2020) A new in-situ method for tracing denitrification in riparian groundwater. Environmental Science & Technology, 54, 3, 1562–1572,


Here we introduce a new Bayesian mixing model that can identify previously unknown end-members.

Keywords: Bayesian end-member mixing modeling, new tracers, inter-aquifer mixing

Citation: Popp, A.L., Scheidegger, A., Moeck, C., Brennwald, S., Kipfer R. (2019) Integrating Bayesian groundwater mixing modeling with on-site helium analysis to identify unknown water sources. Water Resources Research, 55, 12, 10602–10615,


Review on the relevance of the hyporheic zone.

Keywords: hyporheic exchange flow, streambed, ecosystem functioning

Citation: Lewandowski, J., Arnon, S., Banks, E., Batelaan, O., Betterle, A., Broecker, T., Coll, C., Drummond, J.D., Gaona Garcia, J, Galloway, J., Gomez-Velez, J., Grabowski, R.C., Herzog, S.P., Hinkelmann, R., Höhne, A., Hollender, J., Horn, M.A., Jaeger, A., Krause, S., Löchner Prats, A., Magliozzi, C., Meinikmann, K., Mojarrad, B.B., Mueller, B.M., Peralta-Maraver, I., Popp, A.L., Posselt, M., Putschew, A., Radke, M., Raza, M., Riml, J., Robertson, A., Rutere, C., Schaper, J.L., Schirmer, M., Schulz, H., Shanafield, M., Singh, T., Ward, A.S., Wolke, P., Wörman, A. and Wu, L. (2019) Is the hyporheic zone relevant beyond the scientific community?. Water, 11(11), 2230,


Here we assess if dissolved gases are useful to determine groundwater discharge to mountainous streams.

Keywords: mountaineous streams, dissolved gas tracers, groundwater discharge

Citation: Gleeson, T., Manning, A. H., Popp, A., Zane, M., Clark, J. F. (2018) The suitability of using dissolved gases to determine groundwater discharge to high gradient streams. Journal of Hydrology, 557, 561-572,


This study assesses groundwater recharge in a complex geologic setting using a multi-tracer approach.

Keywords: managed aquifer recharge, tracers

Citation: Moeck, C., Radny, D., Popp, A., Brennwald, M., Stoll, S., Auckenthaler, A., Berg, M., Schirmer, M. (2017) Characterization of a managed aquifer recharge system using multiple tracers. Science of the Total Environment, 609, 701-714,