Jana von Freyberg

Jana von Freyberg
École Polytechnique Fédérale de Lausanne | EPFL · School of Architecture, Civil and Environmental Engineering

PhD

About

54
Publications
25,694
Reads
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1,080
Citations
Introduction
My research interests focus on: - The effects of hydrologic connectivity on streamflow regime and solute transport in mountainous headwater catchments - Identification of thresholds and first-order controls driving the rainfall-runoff response at the hillslope- and catchment scale - Effects of climate change on groundwater recharge - Innovative sampling methods in the field - Investigation of water quality variations at high temporal resolution Find out more here: http://www.janavonfreyberg.com
Additional affiliations
June 2018 - October 2018
University of California, Berkeley
Position
  • Researcher
Description
  • - Laboratory experiments to measure the isotope effects in soil water during root water uptake - Close collaboration with the Todd Dawson Lab at UC Berkeley and Erik Oerter at the Lawrence Livermore National Laboratory
March 2015 - April 2020
ETH Zurich
Position
  • PostDoc Position
October 2012 - April 2013
Purdue University
Position
  • Researcher
Description
  • - Quantification of hydrologic connectivity and identification of first-order controls based on data collected at the Swiss Rietholzbach catchment
Education
October 2004 - January 2010
Technische Universität Berlin
Field of study
  • Applied Geosciences and Geo-Engineering

Publications

Publications (54)
Preprint
Relationships between nitrate concentrations and discharge rates (C-Q) at the catchment outlet can provide insights into sources, mobilization and biogeochemical transformations of nitrate within the catchment. Nitrate C-Q relationships often exhibit considerable scatter that might be related to variable hydrologic conditions during runoff events a...
Article
Full-text available
Time series of the natural isotopic composition ( ² H, ¹⁸ O) of precipitation and streamwater can provide important insights into ecohydrological phenomena at the catchment scale. However, multi-year, high-frequency isotope datasets are generally scarce, limiting our ability to study highly dynamic short-term ecohydrological processes. Here we pres...
Article
When the observation of small headwater catchments in the pre‐Alpine Alptal valley (central Switzerland) started in the late 1960s, the researchers were mainly interested in questions related to floods and forest management. Investigations of geomorphological processes in the steep torrent channels followed in the 1980s, along with detailed observa...
Article
Full-text available
Automated field sampling of streamwater or precipitation for subsequent analysis of stable water isotopes (2H and 18O) is often conducted with off-the-shelf automated samplers. However, when water samples are stored in the field for days and weeks in open bottles inside autosamplers, their isotopic signatures can be altered by evaporative fractiona...
Article
Full-text available
Stable isotope ratios of water (𝛿18O,𝛿2H) have long been used to study a core question in plant ecology and ecohydrology: “From where do plants take up water?” Indeed, decades of research has involved sampling potential plant water sources in the subsurface, classifying those sources as distinct endmembers (e.g., deep versus shallow soil waters), a...
Preprint
Full-text available
Automated field sampling of streamwater or precipitation for subsequent analysis of stable water isotopes (2H and 18O) is often conducted with off-the-shelf automated samplers. However, water samples stored in the field for days and weeks in open bottles inside autosamplers undergo isotopic fractionation and vapor mixing, thus altering their isotop...
Article
Full-text available
Studying the response of streamwater chemistry to changes in discharge can provide valuable insights into how catchments store and release water and solutes. Previous studies have determined concentration–discharge (cQ) relationships from long-term, low-frequency data of a wide range of solutes. These analyses, however, provide little insight into...
Article
Full-text available
Recent virtual and experimental investigations have shown that the young water fraction Fyw (i.e. the proportion of catchment outflow younger than circa 2–3 months) increases with discharge in most catchments. The discharge sensitivity of Fyw has been defined as the rate of increase in Fyw with increasing discharge (Q) and has been estimated by the...
Preprint
Full-text available
Abstract. Studying the response of streamwater chemistry to changes in discharge can provide valuable insights into how catchments store and release water and solutes. Previous studies have determined concentration-discharge (cQ) relationships from long-term, low-frequency data of a wide range of solutes. These analyses, however, provide little in...
Conference Paper
Full-text available
This poster presents field-based data from a snow-dominated, pre-Alpine catchment in central Switzerland. We have found that snowpacks under forest cover were roughly 60% shallower and isotopically heavier (roughly 13‰ in δ2H and 2‰ in δ18O) than snowpacks in adjacent open grasslands. Canopy interception effects played a major role in these volumet...
Article
Full-text available
The stable water isotopes, 2H and 18O, can be useful environmental tracers for quantifying snow contributions to streams and aquifers, but characterizing the isotopic signatures of bulk snowpacks is challenging because they can be highly variable across the catchment landscape. In this study, we investigate one major source of isotopic heterogeneit...
Article
Full-text available
Recent virtual and experimental investigations have shown that the young water fraction Fyw (i.e. the proportion of catchment outflow younger than circa 2–3 months) increases with discharge in most catchments. The discharge sensitivity of Fyw has been defined as the rate of increase in Fyw with increasing discharge (Q), and has been estimated by th...
Article
Full-text available
Quantifying the relative contributions of winter versus summer precipitation to streamflow may be important for understanding water‐resource sensitivity to precipitation variability. Here we compare volume‐weighted mean δ18O values in precipitation and streamflow for 12 catchments in Switzerland, to determine whether summer or winter precipitation...
Article
Environmental tracer data, such as the stable water isotopic composition of streamwater and precipitation, are valuable for understanding runoff generation processes and calibrating hydrological models. Despite recent technical advancements, the collection and analysis of streamwater and precipitation samples still involve significant costs and eff...
Article
Full-text available
This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, p...
Article
Full-text available
Rain-on-snow (ROS) events in mountainous catchments can cause enhanced snowmelt, leading to an increased risk of destructive winter floods. However, due to differences in topography and forest cover, the generation of snowpack outflow volumes and their contribution to streamflow are spatially and temporally variable during ROS events. In order to a...
Article
Topography and landscape characteristics affect the storage and release of water and, thus, groundwater dynamics and chemistry. Quantification of catchment‐scale variability in groundwater chemistry and groundwater dynamics may therefore help to delineate different groundwater types and improve our understanding of which parts of the catchment cont...
Preprint
Rain-on-snow (ROS) events in mountainous catchments can cause enhanced snowmelt, leading to destructive winter floods. However, due to differences in topography and vegetation cover, the generation of snowpack outflow and its contribution to streamflow is spatially and temporally variable during ROS events. In order to adequately predict such flood...
Experiment Findings
Following data sets were measured between 2011 and 2014 and are available for research purposes upon request: - Groundwater table depths along the transect, 15min temporal resolution* - Electrical conductivity in groundwater and river water, 15min temporal resolution* - Temperature in groundwater and river water, 15min temporal resolution* - pH...
Poster
Full-text available
Many catchment hydrology studies use stable water isotopes as conservative tracers to track the relative contributions of recent precipitation (event water) in streamflow and to infer dominant runoff processes. Here we present two alternative approaches for using stable water isotopes to better understand how catchments store and release water: est...
Article
Full-text available
Catchment response to precipitation is often investigated using two-component isotope-based hydrograph separation, which quantifies the contribution of precipitation (i.e., event water Qe) or water from storage (i.e., pre-event water Qpe) to total discharge (Q) during storm events. In order to better understand streamflow-generating mechanisms, two...
Article
Full-text available
In this commentary, we summarize and build upon discussions that emerged during the workshop "Isotope-based studies of water partitioning and plant-soil interactions in forested and agricultural environments" held in San Casciano in Val di Pesa, Italy, in September 2017. Quantifying and understanding how water cycles through the Earth's critical zo...
Preprint
Full-text available
Streamflow response to precipitation is often investigated using isotope-based hydrograph separation, which quantifies the contribution of precipitation (i.e., event water Qe) or water from storage (i.e., pre-event water Qpe) to total discharge (Q) during storm events. In order to better understand streamflow generating mechanisms, hydrograph separ...
Article
Full-text available
The young water fraction Fyw, defined as the proportion of catchment outflow younger than approximately 2–3 months, can be estimated directly from the amplitudes of seasonal cycles of stable water isotopes in precipitation and streamflow. Thus, Fyw may be a useful metric in catchment inter-comparison studies that investigate landscape and hydro-cli...
Article
Full-text available
In this commentary, we build on discussions that emerged during the workshop "Isotope-based studies of water partitioning and plant-soil interactions in forested and agricultural environments" held in San Casciano Val di Pesa, Italy, in September 2017. Quantifying and understanding how water cycles through the Earth's critical zone is important to...
Article
Full-text available
Stable water isotopes are widely used in ecohydrology to trace the transport, storage, and mixing of water on its journey through landscapes and ecosystems. Evaporation leaves a characteristic signature on the isotopic composition of the water that is left behind, such that in dual-isotope space, evaporated waters plot below the local meteoric wate...
Article
Full-text available
The contribution of snow meltwater to catchment streamflow can be quantified through hydrograph separation analyses for which stable water isotopes (18O, 2H) are used as environmental tracers. For this, the spatial and temporal variability of the isotopic composition of meltwater needs to be captured by the sampling method. This study compares an o...
Article
Full-text available
Stable water isotopes are widely used in ecohydrology as tracers of the transport, storage, and mixing of water on its journey through landscapes and ecosystems. Evaporation leaves a characteristic signature on the isotopic composition of the water that is left behind, such that in dual-isotope space, evaporated waters plot below the Local Meteoric...
Conference Paper
Full-text available
Comparing catchments' hydrologic responses to their physiographic properties and climatic forcing helps to identify dominant controls on water storage and streamflow generation mechanisms. Here, we used the young water fraction (Fyw), i.e. the fraction of streamflow younger than roughly 3 months, for a catchment inter-comparison study across 22 sit...
Conference Paper
Full-text available
In times where video cameras are installed everywhere and GSM connections are widely available also in remote regions in the Swiss Alps, it is possible to sit in front of a desktop and contemplate how field observations are processing. So, the "big brother" hydrologist is actually most often a dry hydrologist collaborating with wet and MacGyver hyd...
Article
Full-text available
The young water fraction Fyw, defined as the proportion of catchment outflow younger than ca. 2-3 months, can be estimated directly from the amplitudes of seasonal cycles of stable water isotopes in precipitation and streamflow. Thus, Fyw may be a useful metric in catchment inter-comparison studies that investigate landscape and hydro-climatic cont...
Conference Paper
Full-text available
A significant number of groundwater recharge models exist that vary in terms of complexity (i.e. structure and parametrization). Typically, model selection and conceptualization is very subjective and can be a key source of uncertainty in the recharge simulations. Another source of uncertainty is the implicit assumption that model parameters, calib...
Conference Paper
Full-text available
In the pre-Alpine Alptal catchment in central Switzerland, snowmelt and rainfall events cause rapid changes not only in hydrological conditions, but also in water quality. A flood forecasting model for such a mountainous catchment thus requires process understanding that is informed by high-frequency monitoring of hydrological and hydrochemical par...
Conference Paper
Full-text available
In mountainous catchments with seasonal snowpacks, river discharge in downstream valleys is largely sustained by snowmelt in spring and summer. Future climate warming will likely reduce snow volumes and lead to earlier and faster snowmelt in such catchments. This, in turn, may increase the risk of summer low flows and hydrological droughts. Improve...
Article
Full-text available
High-frequency measurements of solutes and isotopes (18O and 2H) in rainfall and streamflow can shed important light on catchment flow pathways and travel times, but the workload and sample storage artifacts involved in collecting, transporting, and analyzing thousands of bottled samples severely constrain catchment studies in which conventional sa...
Conference Paper
Full-text available
A significant number of groundwater recharge models exist that vary in terms of complexity (i.e. structure and parametrization). Typically, model selection and conceptualization is very subjective and can be a key source of uncertainty in the recharge simulations. Another source of uncertainty is the implicit assumption that model parameters, calib...
Article
Full-text available
High-frequency measurements of solutes and isotopes (¹⁸O and ²H) in rainfall and streamflow can shed important light on catchment flow pathways and travel times, but the workload and sample storage artifacts involved in collecting, transporting, and analyzing thousands of bottled samples severely constrain catchment studies where conventional sampl...
Conference Paper
Full-text available
Fundamental catchment properties, such as storage, mixing and water flow pathways are often described through mean transit times (MTT's) or transit time distributions (TTD's). TTD's are usually inferred from concentrations of conservative tracers in precipitation and streamwater using lumped parameter models. Because of the simplifying assumptions...
Conference Paper
Full-text available
An important question in recharge impact studies is how model choice, structure and calibration period affect recharge predictions. It is still unclear if a certain model type or structure is less affected by running the model on time periods with different hydrological conditions compared to the calibration period. This aspect, however, is crucial...
Conference Paper
Full-text available
Studying rapidly changing hydrochemical signals in catchments can help to improve our mechanistic understanding of their water flow pathways and travel times. For these purposes, stable water isotopes (18O and 2H) are commonly used as natural tracers. However, high-frequency isotopic analyses of liquid water samples are challenging. One must captur...
Conference Paper
Hydrological and bio-geochemical processes in catchments are largely determined by the flow pathways of water through the subsurface. While the properties of the input (precipitation) and the output (streamflow) can be monitored with relatively low expenditure, subsurface flow processes and travel times remain difficult to quantify. A comprehensive...
Article
Full-text available
Sediment sampling for microbial characterization is often associated with cross-contamination. The aim of this study was to assess the suitability of widely used sediment-sampling techniques for obtaining microbially uncontaminat-ed samples from the saturated zone. Three different methods were applied: Continuous percussion drilling, discontinuous...
Article
Full-text available
A reliable prediction of hydrograph responses in mountainous headwater catchments requires a mechanistic understanding of the coupled hydro-climatic processes in these regions. This study shows that only a small fraction of the total area in a pre-Alpine headwater catchment actively regulates streamflow responses to hydro-climatic forcing, which fa...
Thesis
Groundwater systems in mountainous headwater catchments significantly sustain downstream freshwater bodies and therefore play an important role in the regional water cycle. Complex interactions between atmospheric, subsurface and ecological variables occur that determine groundwater quantity and quality as well as streamflow-generation mechanisms a...
Conference Paper
An adequate quantification of groundwater recharge is required for sustainable water resource management and robust hydrological model predictions. However, estimation of the future temporal evolution of groundwater recharge rates at annual, seasonal or daily time scales remains a challenging task due to the strong linkage of infiltration processes...
Article
Full-text available
Hydrological responses in mountainous headwater catchments are often highly non-linear with a distinct threshold-related behavior, which is associated to steep hillslopes, shallow soils and strong climatic variability. A holistic understanding of the dominant physical processes that control streamflow generation and non-linearity is required in ord...
Conference Paper
Full-text available
Mountainous watersheds are characterized by generally high precipitation inputs and very heterogeneous landscape properties, which make them very dynamic hydrologic systems that play an important role in the water cycle. Their groundwater systems sustain downstream baseflow in larger catchments in many parts of the world, particularly in the densel...
Conference Paper
Non-linear hydrological behavior of small mountainous watersheds is often attributed to variable streamflow contributions from different landscape units that differ in subsurface properties, vegetation cover and land use. Within this concept, the role of landscape can be seen as that of a filter, translating hydro-climatic drivers into particular s...
Conference Paper
Full-text available
Non-linear hydrological behavior of small mountainous watersheds is often attributed to variable streamflow contributions from different landscape units that differ in subsurface properties, vegetation cover and land use. Within this concept, the role of landscape can be seen as that of a filter, translating hydro-climatic drivers into particular s...
Conference Paper
In our research, we investigate the first-order controls on the formation of hydrologic connectivity between hillslopes and riparian zones in a small pre-Alpine catchment. Our motivation is to understand how hydrologic connectivity evolves during storm events and droughts to establish a general framework of interdisciplinary interest (e.g., ecology...

Network

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Projects

Projects (5)
Project
. The main aim of WATSON is to collect, integrate, and synthesize current interdisciplinary scientific knowledge on the partitioning and mixing of water in the critical zone taking advantage of the unique tracing capability of water isotopes. These efforts will allow going beyond the current fragmented knowledge providing a novel conceptual framework on the interactions between groundwater recharge, soil water storage, and vegetation transpiration useful for water resources management across a variety of climatic settings. Context: Understanding water exchange within the critical zone, i.e.the dynamic skin of the Earth that extends from vegetation canopy to groundwater, is vital for addressing key environmental problems linked to the sustainable management of water resources. Approach: The Action activities are based on a network of early career and senior scientists from different complementary disciplines who are experts in the use of water isotopes, and stakeholders from governmental agencies and private companies from 19 COST countries and one Near Neighbour Country. Meetings and training events will involve scientists and water managers, facilitating communication between academia and stakeholders, promoting the transfer of the latest scientific findings, and helping to identify research gaps and management priorities. Deliverables: The ultimate goal of the network is to build capacity in the use of robust isotope approaches for water resource management. The deliverables include practical tools, such as maps of groundwater recharge and water sources used by vegetation in different European regions that will enable the translation of scientific cutting-edge knowledge into tangible recommendations to support European agencies responsible for water management in agro-forest systems.
Project
A grand challenge in hydrology is understanding how rainfall is stored in catchments and how stored water eventually becomes streamflow. Decades of studies have shown that the majority of streamflow arises from previously stored water exfiltrating as it is displaced by incoming rainfall. Thus, stream discharge and streamwater quality are tightly coupled to the temporal variations in catchment water storage. However, only few studies have experimentally investigated the relationships between subsurface water storage and streamflow generation at the catchment scale because extensive instrumentations are required for monitoring ground- and streamwater properties. In the TempAqua project, we will utilize the temporary stream network in montane catchments as a natural indicator of catchment water storage variations: the geometry and extent of the temporary stream network demonstrate where flows exceed subsurface hydraulic transmissivity at any point in time. Thus, when subsurface water storages are greatest, the stream network should be most extensive; in contrast, in times of drought when water storages are depleted, the temporary stream network should be least extensive. Until now, experimental data sets on temporary stream networks dynamics are rare because data collection faces several challenges: visual mapping of actively flowing streams can be very subjective and time consuming; aerial surveys are not practical in forested or snow-covered terrain or during precipitation events; satellite images are too coarse to distinguish small headwater channels (<0.5m width) from the surrounding landscape and are not usable when clouds cover the view. Therefore, in this project, we will continuously map temporary stream networks through wireless sensor network technology in multiple montane headwater catchments in Switzerland with the ultimate goal to infer how different storages in the landscape release water into streams. In addition, hydrochemical data and stable water isotopes will be used as environmental tracers to quantify the dominant flow pathways and water sources that contribute to streamflow. Finally, the linkages between catchment storage variations and temporary stream networks will be explored through numerical hydrological modeling frameworks. The catchment models will then serve as hypothesis-testing tools to assess how future climate change will affect water availability in the montane study regions. The outcomes of this project will have great relevance for improving our process understanding of water sources, biogeochemical fluxes, and ecological habitat resilience in mountainous environments - under actual and prospective future conditions.
Project
The Rietholzbach Research catchment (RHB) is a small pre-Alpine catchment located in the headwaters of the Swiss Thur River basin. The RHB covers an area of approx. 3.14 km2 and an altitude range from 682 to 950 m. The local climate is characterized by temperate humid conditions with high rainfall rates in late spring and summer. The landscape is mainly characterised by grassland (more than 2/3 of the area is used as pastureland) and forests. The geology is composed of the Tertiary Upper Freshwater Molasse (UFM) that forms steep slopes and plateaus at higher elevations. Pleistocene glacial moraine deposits (GMD) overlay the UFM in the valley bottom. The dominant soil types in the catchment are Regosols on the UFM, and Cambisols on the lower slopes of the GMD. Gelysols and peatysoils can be found at the flat valley bottom areas. Hydrological research in the RHB began in the late 1970's, when is was equipped with three river gauging stations (one of which is maintained by the BAFU), a meteorological station and a larger weighting lysimeter (field site Buel). Between 2011 and 2013, I installed 18 groundwater observation wells along the hillslope near the field site Bel to study the role of groundwater for streamflow generation and solute transport. ​