Know more

About cookies

What is a "cookie"?

A "cookie" is a piece of information, usually small and identified by a name, which may be sent to your browser by a website you are visiting. Your web browser will store it for a period of time, and send it back to the web server each time you log on again.

Different types of cookies are placed on the sites:

  • Cookies strictly necessary for the proper functioning of the site
  • Cookies deposited by third party sites to improve the interactivity of the site, to collect statistics

Learn more about cookies and how they work

The different types of cookies used on this site

Cookies strictly necessary for the site to function

These cookies allow the main services of the site to function optimally. You can technically block them using your browser settings but your experience on the site may be degraded.

Furthermore, you have the possibility of opposing the use of audience measurement tracers strictly necessary for the functioning and current administration of the website in the cookie management window accessible via the link located in the footer of the site.

Technical cookies

Name of the cookie


Shelf life

CAS and PHP session cookies

Login credentials, session security



Saving your cookie consent choices

12 months

Audience measurement cookies (AT Internet)

Name of the cookie


Shelf life


Trace the visitor's route in order to establish visit statistics.

13 months


Store the anonymous ID of the visitor who starts the first time he visits the site

13 months


Identify the numbers (unique identifiers of a site) seen by the visitor and store the visitor's identifiers.

13 months

About the AT Internet audience measurement tool :

AT Internet's audience measurement tool Analytics is deployed on this site in order to obtain information on visitors' navigation and to improve its use.

The French data protection authority (CNIL) has granted an exemption to AT Internet's Web Analytics cookie. This tool is thus exempt from the collection of the Internet user's consent with regard to the deposit of analytics cookies. However, you can refuse the deposit of these cookies via the cookie management panel.

Good to know:

  • The data collected are not cross-checked with other processing operations
  • The deposited cookie is only used to produce anonymous statistics
  • The cookie does not allow the user's navigation on other sites to be tracked.

Third party cookies to improve the interactivity of the site

This site relies on certain services provided by third parties which allow :

  • to offer interactive content;
  • improve usability and facilitate the sharing of content on social networks;
  • view videos and animated presentations directly on our website;
  • protect form entries from robots;
  • monitor the performance of the site.

These third parties will collect and use your browsing data for their own purposes.

How to accept or reject cookies

When you start browsing an eZpublish site, the appearance of the "cookies" banner allows you to accept or refuse all the cookies we use. This banner will be displayed as long as you have not made a choice, even if you are browsing on another page of the site.

You can change your choices at any time by clicking on the "Cookie Management" link.

You can manage these cookies in your browser. Here are the procedures to follow: Firefox; Chrome; Explorer; Safari; Opera

For more information about the cookies we use, you can contact INRAE's Data Protection Officer by email at or by post at :


24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal Logo SAS Logo de l'Institut Agro Rennes-Angers

Home page



Scientist (Post-doc) at SAS


Address: UMR SAS, 65 rue de St-Brieuc, CS 84215, 35042 Rennes Cedex, France

Fields of expertise: Hydrology and biogeochemistry in headwater catchments, in-stream processes, hyporheic exchange, low-cost sensor development

Keywords: Solute transport in headwater catchments, hydrological fluxes and biogeochemical processes in the hyporheic zone, groundwater – surface-water interactions, stream metabolism, high-frequency solute dynamics, carbon, nutrient


Current Research Topics

My research topics are hydrology and biogeochemistry in headwater catchments and in-stream processes in low-order streams. I am interested in understanding the drivers of hydrological flow path activation and solute transport in contrasting headwater catchments (agricultural, tile-drained, forested). I am using timeseries of high-frequency (< 60 min) chemical data at the catchment outlet, in combination with hydrometric and geochemical data from piezometers and groundwater wells, distributed in the catchment.

I am also interested in bedform driven hyporheic exchange and solute transformation (C, nutrients) at the groundwater – surface-water interface as well as drivers of in-stream metabolism (PhD thesis). I use mulit-level piezometers, tracer injections, isotopic and geochemical signatures as well as self-built low-cost conductance sensors to explore these questions.

Current Projects

National innovative equipment infrastructure for spatial and temporal monitoring of the Critical Zone « CRITEX » (Post-Doc). I am using the high-frequency chemical data collected by the three Riverlabs at the AgrHyS (Naizin), ORACLE (Orgeval), and OHGE (Aubure) observatories, with collaborators at Géosciences Rennes (Rennes), UMR IPGP (Paris), UR HYCAR (Antony) and UMR LYGHES (Strasbourg).

Teaching Experience

Classes about tracer injections (travel time and flow paths) and discharge measurements at the Catchment Science Summer School (coordinated by Dr. Jeff McDonnell).


Windsor, F. M., Docherty, C. L., Brekenfeld, N., … (2021): Hydrological, physicochemical and metabolic signatures in groundwater and snowmelt streams in the Japanese Alps. Jounal of Hydrology, 600.

Navratil, O., Brekenfeld, N.,… (2021): Distribution of Asian knotweeds on the Rhône River basin, France: A multi-scale model of invasibility that combines biophysical and anthropogenic factors. Science of The Total Environment, 763.

MacKenzie, A. R., …, Brekenfeld, N., … (2021): BIFoR FACE: Water–soil–vegetation–atmosphere data from a temperate deciduous forest catchment, including under elevated CO2. Hydrological Processes, 35 (3).

Comer-Warner, S. A., Blaen, P. J., Brekenfeld, N., … (2021): Advection Not Dispersion and Transient Storage Controls Streambed Nutrient and Greenhouse Gas Concentrations. Frontiers in Water.

Ward, A. S., Zarnetske, J. P., Baranov, V., Blaen, P. J., Brekenfeld, N.,… (2019): Co-located contemporaneous mapping of morphological, hydrological, chemical, and biological conditions in a 5th-order mountain stream network, Oregon, USA. Earth Syst. Sci. Data, 11, 1567–1581.

Ward, A., S., …, Brekenfeld, N., … (2019): Spatial and temporal variation in river corridor exchange across a 5th-order mountain stream network. Hydrol. Earth Syst. Sci., 23, 5199–5225.

Blaen, J. P., Brekenfeld, N. (shared first author), Comer-Warner, S., Krause, S. (2017): Multitracer Field Fluorometry: Accounting for Temperature and Turbidity Variability During Stream Tracer Tests. Water Resources Research, 53 (11), 9118-9126.