Michael Stoelzle

Michael Stoelzle
University of Freiburg | Albert-Ludwigs-Universität Freiburg · Faculty of Environment and Natural Resources

Dr. rer. nat.
Hydrologist with focus on Droughts, Groundwater and Baseflow...

About

58
Publications
27,243
Reads
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518
Citations
Introduction
Research: Drought and Low Flow research, Hydrological Extremes, Baseflow separation, GW/SW-interaction, Environmental Data and Data Visualization, Programming (R), GIS
Additional affiliations
January 2015 - present
University of Freiburg
Position
  • Researcher
January 2015 - present
University of Freiburg
Position
  • Master's Student
Description
  • Data Collection, Data Management, Data Storage, Data Visualization
January 2014 - present
University of Freiburg
Position
  • PostDoc Position
Education
October 2002 - September 2008
University of Freiburg
Field of study
  • Hydrology (Dilpoma), Statistics, Meteorology

Publications

Publications (58)
Poster
Full-text available
Stress testing scenarios are a valuable alternative to conventional climate scenarios. “Stress” means recharge reduction before drought, “Test” means a quantification of ”Stress”-effect on the drought year (e.g. deficit, recovery, minimum flow). Scenarios are embedded in a HBV model framework to compare streamflow series from scenario runs with str...
Article
Full-text available
Understanding components of the total streamflow is important to assess the ecological functioning of rivers. Binary or two-component separation of streamflow into a quick- and slow (often referred to as baseflow) component, and the associated and often used baseflow index (BFI), have been criticised for their arbitrary choice of separation paramet...
Preprint
Full-text available
Nowadays color in scientific visualizations is standard and extensively used to group, highlight or delineate different parts of data in visualizations. The rainbow color map (also known as jet color map) is famous for its appealing use of the full visual spectrum with impressive changes in chroma and luminance. Beside attracting attention, science...
Article
Full-text available
Elevated nitrate concentrations in groundwater are a common challenge for water management. One important factor in this context is higher frequencies and intensities of wet-dry cycles that may cause increased nitrate concentrations in groundwater due to nitrate flushes after drought termination. Yet systematic studies on regional-scale impacts of...
Article
Full-text available
Die Befragung von Akteuren hilft, Auswirkungen des Klimawandels auf verschiedene Arbeitsbereiche besser zu verstehen und die Sicht der Betroffenen in die Klimafolgen forschung einzubinden. Ziel der hier vorgestellten Umfrage unter verschiedenen Akteursgruppen in Baden-württemberg war es, sowohl die wassernutzung als auch die Verwund- barkeit durch...
Article
Full-text available
Risk management has reduced vulnerability to floods and droughts globally1,2, yet their impacts are still increasing³. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data4,5. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we sh...
Article
Full-text available
Drought events and their impacts vary spatially and temporally due to diverse pedo-climatic and hydrologic conditions, as well as variations in exposure and vulnerability, such as demographics and response actions. While hazard severity and frequency of past drought events have been studied in detail, little is known about the effect of drought man...
Article
Full-text available
Droughts often have a severe impact on the environment , society, and the economy. The variables and scales that are relevant to understand the impact of drought motivated this study, which compared hazard and propagation characteristics, as well as impacts, of major droughts between 1990 and 2019 in southwestern Germany. We bring together high-res...
Poster
Full-text available
Konsistente, umfassende Datensätze für hydro-meteorologische Analysen in Einzugsgebieten haben sowohl die Forschung als auch die Lehre in der Hydrologie in den letzten Jahren geprägt und maßgeblich vorangebracht. Besonders der CAMELS-US Datensatz (Catchment Attributes and MEteorology for Large-Sample studies; 671 Einzugsgebiete verteilt über die US...
Article
Full-text available
Ein neuer, räumlich verteilter, prozessbasierter Ansatz zur Quantifizierung der Grundwasserneubildung wird vorgestellt. Der Anteil der Grundwasserneubildung am Gesamtabfluss, bestehend aus Oberflächenabfluss, Zwischenabfluss und Grundwasserabfluss, wird als Grundwasser-Neubildungs-Index (GwN-I) definiert. Er unterscheidet sich von dem, normalerweis...
Article
Full-text available
Drought events and their impacts vary spatially and temporally due to diverse pedo-climatic and hydrologic conditions, as well as variations in exposure and vulnerability, such as demographics and response actions. While hazard severity and frequency of past drought events have been studied in detail, little is known about the effect of drought man...
Preprint
Full-text available
Droughts often have a severe impact on environment, society, and economy. Only a multifaceted assessment of such droughts and their impacts can provide insights in the variables and scales that are relevant for drought management. Motivated by this aim, we compared hazard and propagation characteristics as well as impacts of major droughts between...
Preprint
Full-text available
Drought events and their impacts vary spatially and temporally due to diverse pedo-climatic and hydrologic conditions, as well as variations in exposure and vulnerability, such as demographics and response actions. While hazardous severity and frequency of past drought events have been studied in detail, little is known about the effect of drought...
Article
Full-text available
Nowadays color in scientific visualizations is standard and extensively used to group, highlight or delineate different parts of data in visualizations. The rainbow color map (also known as jet color map) is famous for its appealing use of the full visual spectrum with impressive changes in chroma and luminance. Besides attracting attention, scienc...
Research
Full-text available
DRIeR – Zahlen und Fakten stellt Schlüsselergebnisse des Projektes auf Factsheets von je zwei Seiten pro Thema zusammen. Beginnend mit einer Kernaussage werden die Forschungsthemen und Ergebnisse präsentiert. Weitergehende Informationen und eine Übersicht über publizierte Fachartikel sind auf www.drier.uni-freiburg.de zu finden.
Article
Full-text available
Groundwater is the main source of freshwater and maintains streamflow during drought. Potential future groundwater and baseflow drought hazards depend on the systems' sensitivity to altered recharge conditions. We performed groundwater model experiments using three different generic stress tests to estimate the groundwater and baseflow drought sens...
Article
Full-text available
The stable isotopes of oxygen and hydrogen, 18O and 2H, provide information on water flow pathways and hydrologic catchment functioning. Here a data set of time series data on precipitation and streamflow isotope composition in medium-sized Swiss catchments, CH-IRP, is presented that is unique in terms of its long-term multi-catchment coverage alon...
Conference Paper
Full-text available
Hydrological processes and water security in a changing world Stress testing as complement to climate scenarios: recharge scenarios to quantify streamflow drought sensitivity Abstract. Precipitation deficits and temperature anomalies are often the main cause for low flows and summer streamflow droughts. However, where groundwater is the main contri...
Article
Full-text available
Precipitation deficits and temperature anomalies are often the main cause for low flows and summer streamflow droughts. However, where groundwater is the main contribution to sustain water availability and ecological integrity during dry spells, the role of recharge and catchment storage is crucial to understand streamflow drought sensitivity. Here...
Preprint
Full-text available
Groundwater is the main source of freshwater and maintains streamflow during drought. Potential future groundwater and baseflow drought hazards depend on systems' sensitivity to altered recharge conditions. We performed groundwater model experiments using three different generic scenarios to estimate the groundwater- and baseflow drought sensitivit...
Technical Report
Full-text available
Baden-Württemberg war 2018 von einer außergewöhnlichen Dürre betroffen, welche vielerorts zu erhöhtem Druck auf die Wasserressourcen führte. Landesweit lagen die Niederschläge bei 50 bis 60 % des langjährigen Mittels. Inwiefern die sinken- de Verfügbarkeit der Wasserressourcen mit Spannungen bei der Wasserverteilung einhergeht wird augenblicklich i...
Preprint
Full-text available
Abstract. The stable isotopes of oxygen and hydrogen, <sup>2</sup>H and <sup>18</sup>O, provide information on water flow pathways and hydrologic catchment functioning. Here a data set of time series data on precipitation and streamflow isotope composition in Swiss medium-sized catchments, CH-IRP, is presented that is unique in terms of its long-te...
Conference Paper
Full-text available
Dry spells and heat waves control the frequency and duration of streamflow drought events. Groundwater storage and release in catchments can modulate their timing and severities in terms of deficit volume and persistence. To better understand the role of recharge and groundwater storage for catchment sensitivity to droughts we investigate the effec...
Article
Full-text available
Understanding components of the total streamflow is important to assess the ecological functioning of rivers. Binary or two-component separation of streamflow into a quick and a slow (often referred to as baseflow) component are often based on arbitrary choices of separation parameters and also merge different delayed components into one baseflow c...
Article
Full-text available
Für hydrologische und wasserwirtschaftliche Fragestellungen wird eine Vielzahl von Modellen mit unterschiedlichsten Konzeptionen und Prozessabbildungen eingesetzt. Vorgestellt werden die Ergebnisse einer Online-Umfrage zur Modellklassifizierung und Charakterisierung der Modellstärken und -schwächen.
Poster
Full-text available
Das Jahr 2018 war in weiten Teilen Europas durch extreme Trockenheit geprägt. Eine Ereignisanalyse für Baden-Württemberg im Rahmen des Projekts DRIeR analysiert physische Ausprägungen der Dürre im Zuammenhang mit dem breiten Spektrum ökologischer und sozio-ökonomischer Folgen.
Poster
Full-text available
The drought of 2018 caused a wide range of impacts on environment and economy. This contribution explores how different drought impacts were linked to the occurrence of extreme values of hydrometeorological indices. Focusing on Germany, this study is based on drought impact data collected from text reports that are archived in the European Drought...
Conference Paper
Understanding streamflow components is important to assess ecological functioning of rivers. Streamflow components can be separated based on tracers or solutes, but also with hydrograph separation. Binary or two-component hydrograph separation of the total streamflow into a quick- and baseflow component and the associated baseflow index (BFI) have...
Article
Hydrologists and hydrogeologists both study the flux and storage of water with the numerous interactions and feedback mechanisms of surface water and groundwater. Traditionally however, focus, models and scales of the studies differ. With this commentary, situations should be illustrated in which the boundary conditions that each discipline assumes...
Poster
Full-text available
Low flows and streamflow droughts are the result of decreased recharge and a depleted outflow of water stored in the catchment. This response modifies climate and can vary strongly among catchments. By direct alteration of pre-drought recharge, rather than climate variables, two storyline-type model experiments test explicitly the sensitivity of st...
Technical Report
Full-text available
Ziel des hier vorgelegten Niedrigwasser-Syntheseberichts ist die Darstellung der wichtigsten Ergebnisse aus den Niedrigwasser-Pilotstudien der drei Bundesländer Baden-Württemberg, Bayern und Rheinland-Pfalz im Rahmen von KLIWA. KLIWA ist eine Kooperation mit dem Titel „Klimaveränderung und Konsequenzen für die Wasserwirtschaft“. Die Pilotstudien be...
Conference Paper
Full-text available
Klimamodelle und resultierende Abflussprojektionen zeigen auf, dass sich sommerliche Niedrigwasserperioden in Süddeutschland zukünftig verstärken können. Die möglichen Veränderungen beziehen sich dabei auf längere und intensivere Niedrigwasserperioden, aber auch auf potenzielle Verschiebungen der bisherigen Niedrigwassersaison im Jahresverlauf. Die...
Conference Paper
Niedrigwasserereignis des Jahres 2015 hat erneut die Vulnerabilität der Fließgewässer und ihrer Nutzer gegenüber der Naturgefahr gezeigt. Dennoch sind die öffentliche sowie auch die politische Wahrnehmung von Niedrigwasser vergleichsweise gering. Eine Auseinandersetzung mit dem Umgang mit trockenheitsbedingtem Niedrigwasser und eine Minderung regio...
Poster
Full-text available
Der Rhein ist eines der größten Stromgebiete Europas und weist hohe Abflussvariabilität und unterschiedliche Regime an seinen Pegeln auf. Dadurch sind Vergleiche von Niedrigwasserereignissen aufwendig und lassen sich schwierig visualisieren. Ziel dieser Studie ist daher extreme Niedrigwasserereignisse durch Visualisierungen aufzuarbeiten.
Article
One of the most important functions of catchments is the storage of water. Catchment storage buffers meteorological extremes and inter-annual streamflow variability, controls the partitioning between evaporation and runoff and influences transit times of water. Hydrogeological data to estimate storage are usually scarce and seldom available for a l...
Conference Paper
Full-text available
Alpine catchments are often considered as quickly responding systems where streamflow contributions from subsurface storages (groundwater) are mostly negligible due to the steep topography, low permeable bedrock and the absence of well-developed soils. Many studies in high altitude catchments have hence focused on water stored in snowpack and glaci...
Conference Paper
Full-text available
Starkregenereignisse besitzen hohes Schadenspotential und führen neben Hochwasserereignissen, auch zu Überflutungen, Sturzfluten und Erdrutschen abseits von Gewässern. Aufgrund der hohen räumlichen und zeitlichen Variabilität von Starkregen ist vor allem bei kurzen Dauern von einer mangelnden Warnlage und unzureichender statistischer Information au...
Conference Paper
Full-text available
Global change adversely affects contributions of groundwater aquifers and other delayed sources (e.g. snow- or glacier melt, wetland, lakes) to streamflow. Based on frequency filtering of hydrographs conventional graphical baseflow separation methods (UK-IH- or WMO-method) separate quickflow (< 5 days) and baseflow (> 5 days) from streamflow. The m...
Conference Paper
Full-text available
Knowledge of the baseflow regime is crucial for managing river ecosystems during low flow periods. Then aquatic conditions, water supply or streamflow forecast highly depend on the sustainability, magnitude, timing or rate of change of the groundwater contribution to streamflow, especially in areas of water shortage or with high water demand. This...
Conference Paper
Full-text available
One of the most important functions of catchments is the temporary storage of water, which directly influences runoff dynamics, rainfall-runoff transformation, partitioning of evaporation and runoff fluxes, and accessibility of water to plants. Generally, a large catchment storage is considered beneficial and in particular increases the transit tim...
Article
Previous work has shown that streamflow response during baseflow conditions is a function of storage, but also that this functional relationship varies among seasons and catchments. Traditionally, hydrological models incorporate conceptual groundwater models consisting of linear or non-linear storage-outflow functions. Identification of the right m...
Conference Paper
Streamflow drought depends to a large degree on groundwater recharge and storage depletion. During prolonged dry spells inherent catchment characteristics such as physiography and geology may be significant descriptors of streamflow response and baseflow-relevant subsurface processes. To better predict and preempt potential streamflow droughts, the...
Article
Streamflow drought response depends to a large degree on groundwater recharge. To better predict and preempt streamflow droughts, the relationship between recharge deficit and streamflow response needs to be studied more systematically. We present a combined SVAT and conceptual groundwater model experiment that applies a novel set of recharge scena...
Conference Paper
Full-text available
Streamflow response during baseflow conditions is a function of storage and outflow, but it is also known that this functional relationship varies among catchments and seasons. Traditionally, hydrological models incorporate conceptual groundwater reservoirs consisting of linear or non-linear storage-outflow functions. Identification of the right mo...
Data
Full-text available
Despite the variety of existing hydrological models, low flow prediction is still challenging. Traditionally low flow is predicted by a function of subsurface storage depletion. Thus, model structures are assumed to incorporate different storages, namely aquifer types and their characteristics. Most often operational low flow prediction is based on...
Conference Paper
Full-text available
In hydrological modeling storage-discharge relationships define low flow prediction. During rainless periods and when evapotranspiration is much smaller than discharge, discharge is solely a function of storage depletion. Models often use a given structure of reservoirs and outflow coefficients defining the storage-discharge relationship that are c...
Article
Full-text available
Streamflow recession has been investigated by a variety of methods, often involving the fit of a model to empirical recession plots to parameterize a non-linear storage–outflow relationship based on the d Q /d t − Q method. Such recession analysis methods (RAMs) are used to estimate hydraulic conductivity, storage capacity, or aquifer thickness and...
Article
Full-text available
Streamflow recession has been investigated by a variety of methods, often involving the fit of a model to empirical recession plots to parameterize a non-linear storage-outflow relationship. Such recession analysis methods (RAMs) are used to estimate hydraulic conductivity, storage capacity, or aquifer thickness and to model streamflow recession cu...
Conference Paper
Full-text available
Nature and society are affected by droughts and low flows even in a water-rich region like Baden-Wuerttemberg in Southern Germany. Low flow is a result of water depletion of surface and subsurface reservoirs during times of low or no precipitation. This depletion is visible in the recession limb of the hydrograph. Streamflow during drought flow rec...
Article
The two-dimensional distribution of flow velocities in shallow waters is one of the governing factors for solute transport processes. Thus, a direct and simple experimental method to spatially assess mean flow velocity and dispersion could improve the prediction of solute transport. In an experimentally constructed wetland we identified these varia...
Conference Paper
Full-text available
Streamflow recession analysis methods reveal relationships between catchment storage and discharge when pre-cipitation, evapotranspiration, surface storage and groundwater withdrawals are negligible. The falling limb of a hydrograph typically declines over several orders of magnitude and discharge (Q) versus rate of change (-dQ/dt) relationships il...
Data
Full-text available
Trockenheitsindikatoren, Stakeholder, Akteure, Drought, Befragung

Questions

Questions (4)
Question
Aim: Explain hydrological variability during low flow periods with land use distribution in different catchments.
Using Corine Land Cover (CLC-2012) offers the possibility to categorize catchments' area according to grassland, cropland, forest, urban areas, water bodies etc. Since CLC has 30-40 different subclasses I asked myself what is the best way to aggregate these subclasses into -let's say- 4-6 groups that are most relevant for low flow studies in hydrology. For example, should deciduous forest and deciduous forest have separated classes or not?
If you know recent papers handling land use classification and low flow analysis please comment here.
Question
I am interested in a ready-to-use "tree ring" dataset for Switzerland. Data range at least 2010-1950 and alpine and nival regions/stations (lets say above 1500 or 200 m asl) should be included.
Question
On catchment scale the seasonality of a streamflow regime is controlled by and composed of different water contributions to the stream (such as glacier melt, snow melt, rainfall / event water, groundwater etc). The streamflow regime is also influenced by evapotranspiration etc. What would be your first idea if you only have streamflow data/signal available to identify the snowmelt period (during the year) and/or to estimate the snowmelt contribution according to yearly discharge sums? My focus is on humid catchments on a meso- or regional-scale (lets say 10 to 1000 km^2 with 50yr streamflow data). All suggestions/ideas/methods are welcome (perhaps also what kind of additional data would be helpful to justify your approach, e.g. stream temperature, groundwater level, isotope data....)!
Question
Many baseflow separation methods have been published, more or less applicable to different catchment (or climate) types. What is essential to separate baseflow in snow-dominated alpine catchments (e.g. regarding their high altitudes, mean slopes or physiographic and geological properties...)?

Network

Cited By

Projects

Projects (2)
Project
This scientifc network funded by the German Research Foundation (DFG) aims to improve the process representations in hydrological model structures and to detect limitations in model structures. Therefore a model comparison protocol will be developed. Within this network regular meeting every six months of the 15 members are scheduled. See more detailed project description here: https://www.gfz-potsdam.de/en/section/hydrology/projects/impro-identification-and-analysis-of-process-limitations-in-hydrological-model-structures/
Project
Climate scenarios project changes in precipitation and temperature. Different temporal structures of future climate input can affect low flows, but the sequencing of simulated wet and dry spells is often not altered. In this project pre-drought recharge is decreased in a HBV model framework to test how catchments response to reduced water availability.