Inspiration catalogue

MSc Thesis ideas’ catalogue 2024

Water Resources Research Group

With contributions from GEUS, Geo, IGN – Skov Natur og Biomasse, and Luxembourg Institute of Science and Technology (LIST), and links to many more national and international partners.

MSc Thesis ideas contained in this catalogue

  1. Locating tile drains in agricultural fields using gamma-ray soil sensing
  2. Bestemmelse af infiltrationskapacitet
  3. Hydrological forecasts in real-time warning systems
  4. Adapting to the extreme: Hydrological modelling of climate adaptation
  5. Machine learning for outlier filtering in groundwater time series
  6. Groundwater parks: Modelling the transition from highly intense agriculture to nature
  7. Kortlægning og monitering af hydrologiske forhold, kemisk og geologisk, i oplandet til Tuse Å i forbindelse med Fors kildepladser og spilde- og regnvandsudledninger i Holbæk
  8. Exploring the Effects of Extreme Climate Events on Deep Groundwater Reservoirs through Hydrological Modelling
  9. Can we use water isotopes to derive groundwater age?
  10. Historical trends in groundwater levels – is it getting wetter?
  11. Can soil moisture be used as a predictor of droughts and flashfloods?
  12. PEACE – Modelling and monitoring hydrology and water table dynamics in large Danish peatlands
  13. Hydrological modelling of nutrient-poor peatlands: Bøllemosen
  14. Data-driven estimation of groundwater recharge
  15. Agricultural Droughts in Denmark – Can we model it?
  16. Groundwater recharge below different land cover types
  17. Hydrological modeling for sustainable groundwater management in South Africa
  18. Using groundwater geochemistry in a South African semi-arid catchment to detect the source of groundwater
  19. Hydrological and hydrogeological investigations of Ayad catchment in India
  20. Hydrological modelling in realtime and forecast mode for hydrological planning and warning systems
  21. Collaboration with international research institute
  22. Application of satellite remote sensing data in hydrological models
  23. Climate change effects, mitigation and adaptation
  24. Hydrogeologisk model for Storkøbenhavn
  25. Assessment of Solute Transport at the Field Scale to Safeguard Groundwater Resources
  26. Evaluating Groundwater-Surface Water Exchange through Varied Modeling Approaches
  27. Using Nitrate as a Tracer to Assess Groundwater Vulnerability
  28. Utilizing Tracers to Quantify the Degree of Preferential Leaching during Rainfall Events
  29. Effect of Groundwater Abstraction Near Stream Valleys
  30. Maintaining Sustainable Groundwater Use under Changing Climate (1)
  31. Maintaining Sustainable Groundwater Use under Changing Climate (2)
  32. Your project?

1. Locating tile drains in agricultural fields using gamma-ray soil sensing

Tile drains are used extensively in clayey agricultural soils to ensure optimal soil moisture conditions for maximum crop productivity. By installing tile drains, excess soil water can be removed by maintaining the groundwater table below the root zone.  In Denmark, the use of artificial drainage of agricultural soils employing tiles started around the 1850s and today approximately half of all agricultural fields are drained by tiles or pipes. Unfortunately, the exact layout of the drainage system is not always known and may be important if the system has deteriorated and needs to be repaired. Also, in numerical assessment of water resources, identifying drain locations can help achieve more representative water balance estimates.  To obtain this information, conventional methods such as tile probes or trenching equipment, can be used. However, these are costly and invasive procedures which may cause damage to the drainage system.  

Gamma-ray soil sensing is a method that records the natural emission of gamma radiation from the soil produced by the decay of Potassium-40, Uranium-238 and Thorium-232. The recorded gamma radiation depends mainly on the type of soil, as clay minerals contain higher concentrations of these radioactive nuclides.  However, water in the soil also affects the measured gamma radiation as the gamma rays are attenuated by the water and thereby reduce the signal from the soil. A non-invasive estimation of soil moisture can therefore be deduced from measurements of gamma radiation.

This project aims to evaluate the use of gamma radiation maps to locate the drainage system of one or several agricultural fields with known drainage layouts (such as the PLAP-fields managed by GEUS). By collecting spatial gamma radiation during and after a rainfall event the drains can be delineated as the largest soil moisture change should be found directly above and in close vicinity to the drain pipes.

Contact persons

Mie Andreasen (GEUS, ma@geus.dk), Sachin Karan (GEUS, saka@geus.dk) and Majken Looms Zibar (mcl@ign.ku.dk)

2. Bestemmelse af infiltrationskapacitet

I forbindelse med dimensionering af infiltrationsbassiner eller faskiner, der typisk indgår som en del af en LAR-løsninger (Lokal Afledning af Regnvand), er det grundlæggende at vide hvor hurtigt vandet vil sive ud af bassinet. Dette er naturligvis meget afhængigt af de helt lokale hydrogeologiske forhold. Dimensioneringen foregår i dag typisk på baggrund af ”tommelfingerregler” og/eller infiltrationsforsøg i huller i jorden eller filtersatte boringer. Undersøgelserne er typisk baseret på stærkt forsimplede forsøg.

Det kunne være rigtigt interessant at beskrive infiltration i en faskine/bassin/lavning teoretisk, herunder hvilke hydrogeologiske forhold, der definerer strømningen og ikke mindst hvilke parametre, der er de vigtigste ved dimensioneringen.

Derudover kunne det være interessant at vurdere de traditionelle ”test”-metoder og metoder til fastlæggelse af dimensionsgivende parametre og på den baggrund diskutere validiteten og ikke mindst hvilke forhold de er gældende for.

Det vil være oplagt at der som en del af projektet gennemføres, tolkes og sammenlignes forskellige forsøg, f.eks.: Infiltration i boringer, infiltration i ”hul”, double-ring infiltrometer-forsøg, K-værdi bestemmelse på baggrund af sigtekurver, mv.

Det kunne også være interessant at diskutere i hvilke situationer, der kan være konsekvenser ved at infiltrere regnvand.

Indhold/mål

  • Teoretisk beskrivelse af de hydrogeologiske forhold omkring en faskine. Beskrivelse af vandstrømninger, hvilke hydrogeologiske forhold og parametre der spiller ind. Der kan regnes på det. Der vil være mulighed for at kigge på både umættet og mættet strømning. Det vil være oplagt at anvende grundvandsmodeller til vurdering af de enkelte parametres betydning.
  • Hvordan fastlægges de faktiske hydrogeologiske forhold på en lokalitet. Hvilke tests er relevante, hvordan skal de udføres og hvordan kommer man fra testresultater til parametre, der kan benyttes i dimensioneringen.
  • Anbefaling til hvordan der kan fremskaffes dimensioneringsgrundlag for f.eks. faskiner. Hvilke test giver det mening at lave. Giver det mening at lave dyre tests hvis en ”billig” overdimensionering kan løse problemet?

Det er muligt at dette ikke, overordnet set, har den store geologiske interesse, men der er ingen tvivl om at en grundig forståelse af strømningsforholdene omkring en faskine vil give en detaljeret  hydrogeologisk forståelse, der er anvendelig i rigtigt mange situationer.

Kontaktperson

Anders Korsgaard (NIRAS, AKo@NIRAS.dk) and Majken Zibar (mcl@ign.ku.dk)

3. Hydrological forecasts in real-time warning systems

Hydrological warning systems are gaining increasing attention in Denmark, for example after the disastrous flooding events in Germany in the summer of 2021, or the historically wet winter 2023/24 in Denmark. Hydrological warning can encompass both flood and inundation warning and monitoring and warning of water resources status and drought. For this purpose, since recently, the National Hydrological Model (DK-model) at GEUS is running as a real-time model and with weather forecasts. The weather forecasts used to produce the hydrological forecasts, most importantly forecasts of rainfall, however, can have systematic biases compared to the climate observations that usually are used with the DK-model. This might affect the performance of the DK-model in the forecast period, as it is originally setup and calibrated to the climate observations. Besides that, there is significant uncertainty in the spatio-temporal patterns of weather forecasts: Inevitably, the forecasts are not perfect, and the predicted rainfall amounts and/or locations can be erroneous.

The severity of these aspects with regards to hydrological forecasts remain unexplored for the specific Danish case. They can be relevant both for flood forecasting (with short-term forecast horizons of a few days), or for the monitoring of the hydrological cycle and droughts (with medium-term forecasts up to 15 days or even seasonal forecasts).

As a master student involved in this work you can gain experience on both hydrological model development, operationalization as well as data processing and analysis. A MSc project can contain some of the elements below or combinations of these:

  • Evaluation of general biases and differences in spatio-temporal patterns between precipitation forecasts and historic observations (Klimagrid Danmark). How do these differences affect hydrological model performance?
  • Event-based uncertainty evaluation of precipitation forecasts and their impact on hydrological forecasts. Based on a comparison of data from a forecast archive with observation data. How large is the uncertainty introduced by the forecast on the hydrological output (streamflow in case of flood warning; soil moisture, groundwater levels or streamflow in case of hydrological/drought monitoring)
  • How skillful are short-term forecasts, e.g. for flood warning?
  • How skillful are long-term/seasonal forecasts, g. for drought monitoring? The longer the forecast horizon, the worse typically the forecast skill. At some point, simple forecasting based on average climate starting from initial conditions (e.g. in groundwater levels) can beat weather forecasts.

Contact persons

Raphael Schneider (GEUS, rs@geus.dk), Lars Troldborg (GEUS, ltr@geus.dk), Simon Stisen (GEUS, sst@geus.dk) and Karsten Høgh Jensen (khj@ign.ku.dk)

4. Adapting to the extreme: Hydrological modelling of climate adaptation

Europe has in recent years experienced several hydrological extreme events from flooding to droughts, and climate projections only imply more pronounced extremes in the future, thus the need to adapt to these extremes is more relevant than ever. In Denmark, Værebro Å catchment is repeatedly facing problems with flooding of the downstream areas during periods with high precipitation. The objective of this study is to investigate possible mitigation strategies for flood protection in the catchment while exploring the potential of mitigating drought by infiltration of surface water for subsurface storage by means of retention techniques. Stored subsurface water can be retrieved in periods of drought e.g. irrigation purposes A detailed hydrological model of the catchment can help understand the high stream flow and assess the potential of retention techniques for flood and drought mitigation. The MSc project could contain, setup of a hydrological model, hydrodynamics modelling and application of the model for specific tasks as well as stakeholder involvement.

The MSc-project will be a part of European project on the mitigation and adaption to hydroclimatic extremes (INTERLAYER), and run parallel with the establishment of a Living Lab in Værebro Å catchment, which is a collaboration between GEUS, KU-IGN and Region Hovedstaden.

The MSc project can, e.g., contain some of the elements below or combinations of those:

  • Stakeholder involvement e.g., mapping interests and conflicting demands of citizens, municipalities and industries in the area.
  • Detailed transient groundwater-surface water modeling of Værebro Å catchment in MIKE SHE. Including model setup and calibration.
  • Hydrodynamics modelling of river flow and simulating selected flooding events.
  • Use the hydrological model to investigate e.g.:
    • How can different solutions entail flood protection and contribute to drought mitigation? Such solutions, including nature-based solutions, could be land use change (planting forest), rewetting of peatland areas, water parking, etc.
    • Those solutions could be investigated both under current and future climate conditions.

Contact persons

Tanja Denager (GEUS, tad@geus.dk), Ida Seidenfaden (GEUS, ika@geus.dk) and Majken Zibar (mcl@ign.ku.dk) 

5. Machine learning for outlier filtering in groundwater time series

Good observation time series are essential to understand the hydrological cycle, and to evaluate hydrological models. This for example applies to observations of water level in streams and related streamflow. But also to time series of groundwater levels measured in boreholes, which is what we want to focus on.

At GEUS, we host the Danish national borehole database Jupiter. Observations of groundwater levels reported in the database serve as a basis for the evaluation of the National Hydrological Model (DK-model). Those measurements partly go back several decades, and are reported to the database by different entities without significant quality assurance. Many of those time series contain erroneous values, and manual quality assurance and outlier filtering is difficult due to the sheer number of measurements. Some years ago, at GEUS, we developed a relatively simple outlier filtering method based on machine learning algorithms. As we have to update the data for the DK-model, and machine learning techniques moved on in the last years, we want to re-visit this outlier filtering.

Content

As a master student, you would work together with relevant people from GEUS with experience in different machine learning methods, and who were involved in the initial outlier filtering. Particular challenges of the groundwater level filtering are linked to the (i) local nature of groundwater dynamics, (ii) various anthropogenic influences on groundwater levels, (iii) the partially uneven time steps in the observation time series, and (iv) shortness of time series. A MSc project will contain some of the elements below

  • Analysis of groundwater level time series: Classification of different outlier types, different time series length and groundwater dynamics.
  • Selection of a suitable machine learning algorithm flexible enough for the outlier filtering of groundwater level time series.
  • Application of the outlier filtering algorithm across the national datasets of thousands of time series, and evaluation of its performance.
  • Application of the outlier filtering algorithm on real-time data (grundvandsstanden.dk).
  • Application of the outlier filtering algorithm to other types of data (e.g. streamflow).

Contact persons: Raphael Schneider (GEUS, rs@geus.dk), Simon Stisen (GEUS, sst@geus.dk), Jacob Kidmose (GEUS, jbki@geus.dk) and Søren Jessen (sj@ign.ku.dk)

6. Groundwater parks: Modelling the transition from highly intense agriculture to nature

To protect the drinking water resource in Denmark several groundwater parks are being planned in Denmark. The parks are located in groundwater recharge zones, and generally involve farmland being taken out of practice and converted to nature, such as wetlands, forests and open meadows. The concept is that nitrate and pesticide application will be reduced or removed from the recharge that replenishes the drinking water reserve. Further benefits such as biodiversity, recreational areas and climate adaptation are also a part of the transition. In an ongoing project in Denmark's largest abstraction site, Holmehave, on Funen, we combine well-established and new techniques for monitoring the effect of the upcoming extensive land conversion. The project involves several collaborations with the water utility company and the municipalities. However, to upscale and project the impacts of the conversion, hydrological modelling is needed to track shifts in the hydrological system as the natural landscape grows and to quantify impacts on the groundwater resource. An MSc project can contain some of the elements below or combinations of these:

Ideas/content

  • Fieldwork: Setup and analysis of a hydrological monitoring network with new innovative measuring equipment.
  • Modelling: Detailed hydrological modelling of the area, before and after the transition, including setup and calibration.
  • Modelling: Modelling of energy fluxes, with a focus on the change in evapotranspiration from agriculture to forest.
  • Modelling: Analyzing future hydrology under climate change and more extensive land use conversion.

Contact persons

Torben Sonnenborg (GEUS, tso@geus.dk), Mie Andreasen (GEUS, ma@geus.dk), Ida Seidenfaden (GEUS, ika@geus.dk), Majken Zibar (mcl@ign.ku.dk) and Karsten Høgh Jensen (khi@ign.ku.dk)

7. Kortlægning og monitering af hydrologiske forhold, kemisk og geologisk, i oplandet til Tuse Å i forbindelse med Fors kildepladser og spilde- og regnvandsudledninger i Holbæk

Forsyningsselskabet Fors har flere kildepladser, samt spilde- og regnvandsudledninger, i oplandet til Tuse å-systemet, og har derigennem flere problemstillinger der skal undersøges. Herunder baggrundskoncentrationen af bl.a. tungmetaller i vandløbets vand, referenceafstrømning og vandløbspåvirkning grundet indvinding og udledning, samt de underjordiske grundvandsstrømninger.

Vandløbsvand er en sammensætning af vand fra flere forskellige kilder, bl.a. af grundvandstilstrømning, drænvand og udledning fra renseanlæg og regnvandsbassiner. Indflydelsen fra forskellige vandkilder er bl.a. afhængig af den rumlige variation i hvor grundvandet kan strømme til vandløbet, som igen er afhængig af geologi og trykforhold, variation i arealanvendelsen og nedbørsvariation.

Kendskab til vandløbsvandets sammensætning, og til de forskellige kilders input til vandløbet, kan bl.a. være nyttig ved indvinding af grundvand til drikkevand, hvor vi gerne vil kende påvirkningen fra grundvandsindvinding på vandløbssystem (både rumligt og tidsligt), ligesom man ved spilde- og regnvandsudledning gerne vil kende til vandløbsvandets baggrundskoncentration af forskellige kemiske bestanddele (rumligt og tidsligt).

Projektet vil blive udført med Tuse Å opland (her findes flere målestationer), med kildepladserne Vallestrup, Hellestrup, Sandmosen, Kalvemosen og Knabstrup Enge, samt flere spilde- og regnvandsudledninger i oplandet, som case-område. Vi kunne forestille os at projektet kan blive en kombination af skrivebordsanalyser og feltarbejde. Der eksisterer flere datasæt som skrivebordsanalyserne kunne tage udgangspunkt i bl.a. Jupiter-databasen, Miljødata på Miljøportalen og diverse geologiske og hydrogeologiske kortlægninger. Derudover har Fors data på indvindingsmængder og udledningsmængder, som også vil være tilgængeligt for studiet. Det kan suppleres med forskellige typer af feltarbejde, fx. udtagning af vandprøver og måling af trykniveauer, og der kan muligvis benyttes infrastruktur fra eksisterende moniteringsprogrammer og forskningsprojekter.

Objektiver

  • Kortlægning af bidrag fra forskellige vandkilder til vandløbssystemet og en inddeling i ”vandtypezoner”:
    • Hvor tilstrømmer forskellige vandtyper til vandløbet?
    • Hvordan bidrager forskellige vandkilder til vandløbsvandet i Tuse Å systemet?
    • Hvor strømmer vandløbsvand ud af vandløbet til grundvandet?
  • Kemisk beskrivelse af de forskellige vandtyper, der strømmer til vandløbet.
    • Hvilken vandkemi beskriver de forskellige vandtyper: dybt grundvand, terrænnært grundvand, forskellige overfladevandstyper (drænvand, regnvand og spildevand)? Her er vi især interesseret i zink, selen, kobber, nikkel, arsen, bisphenol A, PAH (kulbrinter), alkylbenzensulfomat og DEHP.
    • Man kan også finde inspiration i ”Typetal for MFS i regnbetingede udledninger.”
  • Sammenligning af kortlægningsresultater (Obj. 1) og vandkemisk beskrivelse af de forskellige vandtyper (Obj. 2), for at se om man kan bruge vandkemi i vandløbene til at validere kortlægningen.

Kontaktpersoner

Katrine Eriksen (FORS, kae@fors.dk), Martin Olsen (FORS, mao@fors.dk) og Søren Jessen (sj@ign.ku.dk)

8. Exploring the Effects of Extreme Climate Events on Deep Groundwater Reservoirs through Hydrological Modelling

With a changing climate, more frequent weather extremes, such as heavy rainfall, flooding, and droughts are to be expected. Denmark experienced a severe drought in the summer of 2018, while the winter of 2023/2024 had record breaking amounts of precipitation. During the recent years, Greater Copenhagen Utility (HOFOR) has observed decreasing groundwater levels in some of the catchments where groundwater is abstracted. Consequently, there is a need to investigate the effects of extreme climate events and changes in rainfall patterns on the deep groundwater resources. The aim is to enhance our understanding and knowledge of what the potential impact of the dry summer of 2018 and wet winter of 2023 on the deep groundwater reservoir is. The project furthermore aims to provide an understanding of whether the wet winter of 2023 can compensate for the dry summer of 2018.

The project will be based on an existing MIKE SHE model to simulate various model scenarios for some of HOFORs catchment areas by using available climate data, hydrological data, and groundwater level data. The MSc thesis will be executed in collaboration with HOFOR and consist of the following:

  • Setup of a hydrological model in MIKE SHE.
  • Validation of the model using a comprehensive time series dataset of groundwater levels and river discharge.
  • Selection and assessment of which extreme climate scenarios to simulate.
  • Scenario simulation of extreme weather conditions.
  • Analysis of how climatic parameters affect the deep limestone groundwater reservoir.
  • Optionally, geological fault lines and their impact on groundwater resources may be analyzed.

Contact persons

Karsten Høgh Jensen (khi@ign.ku.dk), Kristian Bitsch (HOFOR, krbi@hofor.dk) and Lena Ali (HOFOR, lenali@hofor.dk)

9. Can we use water isotopes to derive groundwater age?

Groundwater is derived from rainwater. The isotope signal (the ratio between heavy and light water molecules) of rainwater is a function of the temperature in the cloud where the rain is formed. Global warming leads to an increase in the temperature, implying that the increasing temperature will lead to a change in isotope signal in the groundwater. This means that we may be able to use the water isotope signal of the groundwater to estimate when the infiltration of the water now pumped from a well took place. The isotope signal was measured for all of the GRUMO wells during 2022 (GRUMO is the national groundwater monitoring program). For some of these wells the year of infiltration has been determined using 3H/3He, giving a possibility of making a direct comparison!

In other places a more qualitative comparison can be made based on the depth of the groundwater, possibly supported by data from the “DK-model” of the Danish hydrological system or perhaps other models made in relation to the groundwater resource management of the water works. A nationwide monitoring of the precipitation has slowly started, this should give us an idea of the national variation. At the moment the GRUMO samples from 2022 have been measured – but the results still need to be associated with the wells they come from (something GEUS can hopefully find resources for soon) and then of course the more interesting part is associating the isotope data with existing data from those wells of especially the groundwater age. In addition there is a partial dataset of GRUMO wells from some years ago (Sascha Müller). 

Objectives

  • Objective 1.1: Analyse the literature for similar studies.
  • Objective 1.2: Assist in the establishing of the national precipitation network to obtain the first impression of the national variation in the isotope composition of the precipitation.
  • Objective 1.3: Make the coupling between isotope data and data from the GRUMO wells.
  • Objective 1.4: Extract probable groundwater ages from the DK-model.
  • Objective 1.5: Evaluate the potential of using water isotopes for age estimates of groundwater in a warming (or cooling) world.

Contact persons

Søren Jessen (sj@ign.ku.dk) and Rasmus Jakobsen (GEUS, raj@geus.dk)

10. Historical trends in groundwater levels – is it getting wetter?

In the future mean groundwater levels have been projected to increase substantially for Denmark with potentially large consequences for agriculture, infrastructure and the natural landscape. Municipalities, farmers and society in general already report increasing problems with surface-near groundwater and correlated damages and economic losses. These problems may be related to multiple sources apart from climatic changes, e.g., better-sealed drainage systems in cities, the building of houses and industries on inappropriate land (with naturally high groundwater), climate adaptation efforts and local infiltration of rainfall. However, limited knowledge exists about an underlying current climate-driven trend in groundwater levels as seen in the historical records. So, the fundamental question of whether or not the subsurface is getting wetter or if the human-induced actions dominate remains unknown. Logically it is also unknown whether a potentially registered change is comparable to future projected change. This is mainly related to challenges in identifying time series records of appropriate length, and quality and undisturbed by human activities, irrigation and abstraction efforts.  A MSc project on this would be connected to the drought project, investigating droughts in Denmark could contain some of the elements below or combinations of these:

Ideas/content

  • Identifying potential groundwater level observations for analyzing trends.
  • Applying different trend analyses and significant tests for groundwater time series on different time scales, aquifers and seasons.
  • Investigating trends of groundwater extremes (high and low).
  • Comparing trends with modelled trends by the National Hydrological Model.
  • Based on interest, be part of or write a paper on the historical changes in the groundwater system in Denmark.

Contact persons

Ida Seidenfaden (GEUS, ika@geus.dk), Karsten Høgh Jensen (khj@ign.ku.dk) and Simon Stisen (GEUS, sst@geus.dk).

11. Can soil moisture be used as a predictor of droughts and flashfloods? 

In Denmark, the higher temperatures caused by the changing climate will affect the seasonal precipitation patterns. We can both expect wetter winters and longer and more severe periods of drought during the growing season. The wetter winters may cause high soil moisture levels in the upper soil layers. When the soil becomes saturated additional rainfall may not infiltrate fast enough and the excess water will produce increased quick flow with risk of flooding both locally and at downstream locations. Droughts during the growing season may in turn result in loss of agricultural yield but can also adversely affect natural ecosystems or cause damage to infrastructure (e.g., damage on buildings due to subsidence). In the recent years, both droughts (summers 2018 and 2023) and flashflood events (winters 2019/2020 and 2023/2024) have been recorded with large economic consequences to follow.

Soil moisture data has been collected at six agricultural sites across Denmark since 2000 by GEUS and at three field sites in Skjern characterized by different land covers (agricultural field, heathland and coniferous forest) since 2013/2014 by UCPH. These sites represent different weather regimes and soil types. This project will use data from these sites to investigate whether recorded soil moisture can be used as a predictor of drought and flash floods. The analysis will be data-driven, and will exploit additional data such as regional information of crop yield, floods, and satellite soil moisture data from SMAP.

Contact persons

Majken Looms Zibar (mcl@ign.ku.dk), Ida Karlsson Seidenfaden (GEUS, ika@ign.ku.dk) Mie Andreasen (GEUS, ma@geus.dk)

12. PEACE – Modelling and monitoring hydrology and water table dynamics in large Danish peatlands

The PEACE project deals with the observation and modelling of peatland hydrology and water table dynamics at catchment scale. Based on field observations from Tuse å and Åmosen peatlands (central Sjælland), integrated and transient MIKE SHE models are setup and calibrated to enable simulation of water table depth dynamics in great spatio-temporal detail. Water table depth dynamics are fundamental for estimating GHG emissions from peatlands and understand the impact of rewetting strategies, peatland management and climate change.

A master thesis in connection to this project will be open to a range of topics related to both field work (measuring streamflow, groundwater levels, groundwater temperature, peat depths etc.), satellite remote sensing (mapping surface flooding and soil wetness based on high resolution satellite data and machine learning) and integrated groundwater surface water modelling at catchment scale (model parametrization, calibration and scenario analysis). Particularly, there is potential in increasing our understanding of hydrological variability in the peatlands by combining, fieldwork, data analysis, remote sensing and modelling. In addition, there are good opportunities for analyzing hydrological impacts on peatland GHG emissions including identification of potential hot-spots and hot-moments. 

Contact persons

Simon Stisen (GEUS, sst@geus.dk), Tanja Denager (GEUS), Raphael Schneider (GEUS) and Jesper Riis Christiansen (IGN, jrc@ign.ku.dk) 

13. Hydrological modelling of nutrient-poor peatlands: Bøllemosen

The Bøllemosen bog, located 16 km north of Copenhagen, is encircled by forest and therefore generally nutrient poor. However, there are recent indications of deterioration of its ecological state which call for restorative actions. The bog has been previously biologically characterized, and, regarding nutrient loading, it is clear that the bog receives some nutrients by atmospheric deposition. However, little remains known about the hydrology and hydrogeochemistry of the bog, which may largely control the ecological state of the habitat. Therefore, in the proposed project, the influence of nutrient input from hydrological pathways will be addressed, in an assessment of the hydrogeology of Bøllemosen. Bøllemosen bog is one of 261 protected EU habitats in Denmark. Danish authorities therefore are responsible for securing or improving its ecological state.

Objectives

  • Conduct a literature search to find existing (historical) hydrogeological data regarding Bøllemosen.
  • Monitor a network of piezometers (existing + possibly new) and a rain gauge with respect to hydraulic head and water chemistry and stable isotopes of water.
  • Conduct geophysical investigations in conjuncture with hand drillings and borehole information from existing borehole and create a conceptual hydrogeological model.
  • Monitor the hydrology of surface hydrological features such as ditches, ponds, etc.
  • Integrate the information with existing data to create a conceptual hydrogeological model and a water balance for Bøllemosen.
  • Setup a numerical distributed hydrogeological model for Bøllemosen.

Contact persons

Majken Zibar (mcl@ign.ku.dk) and Søren Jessen (sj@ign.ku.dk)

14. Data-driven estimation of groundwater recharge

In Denmark, 100% of all drinking water is extracted from the groundwater resources. In order to sustainably use this resource, i.e. avoid a lowering of the groundwater table and maintaining the required inflow of groundwater to streams and lakes to ensure these ecosystems, it is necessary to quantify the amount and timing of water recharging the groundwater each year. Unfortunately, groundwater recharge is difficult to measure directly. Instead, this important water flux is typically estimated using hydrological models or by rearranging the water balance equation and using best-estimates of the other water fluxes, i.e.:

Recharge = Precipitation – (Evapotranspiration + Overlandflow + Interflow + Storage change). 

This project will explore the possibilities of using time-series of river discharge to estimate land-cover dependent groundwater recharge in the Ahlergaarde catchment. The first step is to preform a hydrograph separation to remove the amount of river discharge that cannot be assumed to originate from groundwater recharge. Then a multi-station approach will be used to estimate the land-cover dependent recharge of the dominating land cover types in the area, i.e. agriculture, heathland, and forest. Finally, the estimates of recharge will be compared with modelling results from the DK-model and measurements of recharge below an agricultural field within the catchment.

Contact persons

Majken Looms Zibar (mcl@ign.ku.dk), Karsten Høgh Jensen (khj@ign.ku.dk) and Mie Andreasen (GEUS, ma@geus.dk)

15. Agricultural Droughts in Denmark – Can we model it?

During the last century, Denmark has faced severe summer droughts affecting agriculture, ecosystems and infrastructure. As a drought develops over time, it progresses from lack of rainfall (meteorological drought) to drying out of soils (agricultural drought) and into the hydrological system (hydrological drought) manifesting in streams, lakes and groundwater. Recently, the 2018 drought led to substantial crop failure and a demand for higher irrigation permissions and drought risk management. However, soil, geology, vegetation, and depth to the groundwater table all influence the unsaturated zone response to lack of precipitation; and drought resistance, impact, and recovery may differ across the Danish area. Modelling this response correctly is crucial for drought monitoring and mitigation.

The representation of the unsaturated zone in the National Hydrological Model (DK-model) is, as of now, simple. Its capability to accurately simulate the propagation of agricultural droughts and the potential for improving the unsaturated zone description to improve drought modelling is unknown. In particular, when considering the demand on computational power required to implement more sophisticated UZ solutions on a national scale, thus is the improvement worth the effort? The focus of this project is to investigate ways to improve agricultural drought modelling, pointing to processes that have the potential to be implemented in the National Hydrological Model. In this master's project, the student will be connected to the Governmental project on droughts in Denmark, which is a collaboration between GEUS, DMI and SDFI (Styrelsen for Dataforsyning og Infrastruktur). The project could contain some of the elements below or combinations of these:

Ideas/content

  • Creating a submodel of the National Hydrological Model for a catchment with existing soil moisture observations and investigating its simulation of soil moisture particularly during periods of agricultural droughts.
  • Implementing and calibrating the submodel with different unsaturated zone modules (gravity flow, Richards eq.).
  • Testing and comparing the performance of the different submodel versions to historical drought situations, e.g., 2018.
  • Running the models with different future climate change projects to investigate the impact of unsaturated zone processes on future projections of agricultural drought.
  • Exploring remote sensing products of soil moisture or vegetation stress suitable for Danish conditions.

Contact persons

Raphael Schneider (GEUS, rs@geus.dk), Ida Seidenfaden (GEUS, ika@geus.dk), Karsten Høgh Jensen (khj@ign.ku.dk) and Torben Sonnenborg (GEUS, tso@geus.dk)

16. Groundwater recharge below different land cover types

Since the 1990´s, planting forest has become a common water management practice. The change of agricultural land to forest (i.e., afforestation) is used to secure the quality of the underlying groundwater resource by discontinuing the addition of nutrients, pesticides, and PFAS at the surface. In 2020, forest formed 14.7% of the total land cover in Denmark. It is a political goal that by the end of the 21st century, 20-25% of the country should be covered by forest. With increased afforestation, it is important to understand how different land cover types affect the water balance at the surface, and ultimately the groundwater recharge.

In this project 1D hydrological models (MIKE SHE using the SWAT module) will be setup for a unique field location close to Hillerød, i.e. the Frederiksborg ICP forest site. At this site, three different land cover types, i.e. open grassland, deciduous forest, coniferous forest, exist within 200 m of each other. Due to the close proximity, the external forcing of the system and the local geology are expected to be the same. Measurements of local throughfall, soil moisture, groundwater table are available at the three sites and will be used to calibrate the hydrological models to obtain estimates of groundwater recharge.  

Contact persons

Majken Looms Zibar (mcl@ign.ku.dk), Karsten Høgh Jensen (khj@ign.ku.dk) and Mie Andreasen (GEUS, ma@geus.dk)

17. Hydrological modeling for sustainable groundwater management in South Africa

Semi-arid regions are dominated by highly irregular precipitation patterns, which strongly influence the hydrological cycle and water resources availability. Large temporal and spatial variations in precipitation causes large variability in runoff and groundwater recharge. Because of its climatic characteristics the Hout/Sand river catchment in the Limpopo province of South Africa is prone to droughts, and combined with irrigation for intensive agriculture, a growing population and climate change the region is facing severe water challenges. In order to identify sustainable groundwater management scenarios a better understanding of the hydrological processes is required, in particular the replenishment of groundwater.

Several projects can be developed in relation to an on-going Danida funded project in South Africa

  • Further development and calibration of the MIKE SHE model for the study area using both traditional data in the form of river discharge and groundwater levels and remote sensing data such as soil moisture, evapotranspiration and flooding extent. Since the rainfall-runoff relationships are complicated and partially unknown new conceptualizations need to be tested as well as alternative targets for calibration.
  • Replenishment of groundwater can occur as diffuse or focused recharge. Diffuse recharge is recharge that is distributed over the catchment in response to precipitation and in semi-arid areas it often occurs as episodic events. Focused recharge occurs from rivers and managed recharge from e.g. farms and varies significantly in space and time. The two recharge components and their mutual significance at catchment scale should be analyzed using the MIKE SHE model in combination with historical data on groundwater levels as well as data currently collected from two field infrastructures established in the study area.
  • Development of an alternative modelling framework for the study catchment based on MODFLOW-6 incorporated in the GMS system.
  • Analysis of impact of climate change on the hydrological components and on groundwater use and management.
  • Downscaling of the hydrological model simulations to community and farm scale using machine learning techniques to help improving groundwater management at smaller scales.
  • Analysis of reactive transport of a managed recharge site using geochemical modelling.

If relevant, the project can partly cover travel expenses to South Africa.

Contact persons

Elisa Bjerre (elbj@ign.ku.dk), Søren Jessen (sj@ign.ku.dk) and Karsten Høgh Jensen (khj@ign.ku.dk)

18. Using groundwater geochemistry in a South African semi-arid catchment to detect the source of groundwater

Groundwater in many semi-arid regions form by infiltration through the river bed to the aquifer during very short periods of extreme flow. The groundwater formation is therefore focused to occur mainly near the river channel and over short periods of time: so-called focused groundwater recharge.  Sampling of groundwater is currently being undertaken in the Hout/Sand river catchment in the Limpopo province of South Africa. The area is prone to droughts, and their severity are further exacerbated by increasing demands of irrigation water, a growing population and climate change. In this context groundwater potentially serves as a stable source of water during droughts.

This study makes use of analysis of stable isotopes of water and water chemistry to interpret the source of groundwater and in particular the importance of focused recharge. Knowledge derived from this interpretation will aid the sustainable management of water in the changing climate of the region.

Objectives

  • Make maps of electrical conductivity and isotopic signatures.
  • Make figures showing electrical conductivity and isotopic signatures as function of distance to nearest river.
  • Conduct geochemical ‘speciation calculations’ using PHREEQC to derive mineral saturation indices and partial gas pressures.
  • Establish geological models showing the distribution of different lithologies that may affect the groundwater chemistry via rock-water geochemical interactions.
  • Calculate effects of rock-water reactions and compare the results to the chemistry of rain water not affected by rock-water interactions.
  • Derive evaporation using chloride as tracer.
  • Establish a conceptual model explaining the spatial distribution of water with different chemistry and thereby explaining the modes of aquifer recharge.

If relevant, the project can partly cover travel expenses to South Africa.

Contact persons

Søren Jessen (sj@ign.ku.dk), Elisa Bjerre (elbj@ign.ku.dk) and Karsten Høgh Jensen (khj@ign.ku.dk)

19. Hydrological and hydrogeological investigations of Ayad catchment in India

Indian water resources are under strain from increasing population, intensified agricultural production, industrial development, changing food habits with growing income as well as pollution of the surface and subsurface waters. The semi-arid state of Rajasthan is particularly vulnerable. It has 10% of India’s area but only about 1% of the water resources. Although Rajasthan is mainly rural, the rate of urbanization has increased considerably over the last decades. One of the growing urban areas is Udaipur City, which now is the sixth largest city in Rajasthan and also known as the ‘city of lakes’ in India. This has led to increased pressure on the water resources and the Udaipur District is facing serious problems and challenges in securing adequate water supply of acceptable quality and in mitigating pollution of the water resources.

The water supply of the city is unique as it is largely based on water from the lakes around the city.

Proper integrated water resources management in the district is hampered by insufficient knowledge of the overall water balance. The seasonal Ayad River flows through Udaipur City connecting the lakes. The seasonal and annual dynamics of this water system is poorly known and understood. To improve the understanding of the system a hydrological model analysis is required.

The activities are related to an on-going Danida funded project. 

If relevant, the project can partly cover travel expenses to South Africa. 

Objectives

  • Analysis of hydrological and hydrogeological data from the region.
  • Development and calibration of a hydrological model for the study area.
  • Use of remote sensing data such as soil moisture, evapotranspiration and flooding extent for calibration and validation.

Contact persons

Trine Enemark (tre@ign.ku.dk) and Karsten H. Jensen (khj@ign.ku.dk)

20. Hydrological modelling in realtime and forecast mode for hydrological planning and warning systems

Hydrological warning systems are gaining increasing attention in Denmark, especially after the disastrous flooding events in Germany in the summer 2021. Hydrological warning can encompass both flood and inundation warning and warning of water resources status and drought. At GEUS, the national water resources model (DK-Model) is planned to move into both realtime and forecast mode in the coming years. This will require a rethinking of the models setup, calibration and evaluation. In addition, add-on modules for inundation of floodplains must be developed and the whole system should be placed in an operational framework linked to weather forecasts. As a master student involved in this work you can gain experience on both hydrological model development, postprocessing and visualization of data for end-users and operationalization. A Msc project can contain some of the elements below or combinations of these.

Ideas/content

  • Modelling: Improve existing hydrological models for flood forecast or drought. Develop and test model evaluation schemes. Develop automatization schemes for 24/7 model execution and visualization. Develop inundation tools for predicting flood extend in stream valleys.
  • Remote sensing: Develop algorithms for detecting free water surfaces from radar data and compare with model simulations for validation.

Contact persons

Simon Stisen (GEUS, sst@geus.dk) and Karsten Høgh Jensen (khj@ign.ku.dk)

21. Collaboration with international research institute

Research Center Julich in Germany is an international recognized research organization in hydrology and water resources. One of the more recent activities is the development of the Terrestrial Environmental Observatories (TERENO), an activity similar to the Danish Hydrological Observatory HOBE. The main goal of the infrastructure TERENO is to create observation platforms on the basis of an interdisciplinary and long-term aimed research program. A comprehensive array of data collection and research activities is established within the framework of TERENO and Danish students are invited to participate in the experimental and research activities through MSc thesis projects. Funding is available for travel and living expenses.

See https://www.fz-juelich.de/en/ibg/ibg-3?expand=translations,fzjsettings,nearest-institut for more details.

Contact person

Karsten H. Jensen (khj@ign.ku.dk)

22. Application of satellite remote sensing data in hydrological models

Satellite remote sensing data offer temporal and spatially distributed data of land surface characteristics, which can be used for driving, validating or calibrating distributed hydrological models. This study will explore the use of data from different satellite types in hydrological modeling on variable spatial scales either in Denmark or internationally. Satellite data can be utilized for deriving spatially consistent time series of relevant model input such as rainfall, potential evapotranspiration, vegetation and albedo. In addition valuable spatial pattern information can be derived from input such as land surface temperature and estimates evapotranspiration for hydrological model evaluation.

Objectives

  • Deriving hydrological relevant variables from remote sensing data.
  • Testing different types of data for different problems.
  • Application of remote sensing data in distributed hydrological models.
  • Spatial pattern evaluation and calibration of hydrological models.

Contact person

Karsten H. Jensen (khj@geo.ku.dk), Simon Stisen (GEUS, sst@geus.dk) and Julian Koch (GEUS, juko@geus.dk)

23. Climate change effects, mitigation and adaptation

Many urban areas and landscapes are facing problems with flooding due to high water levels in streams and high groundwater levels in consequence of increasing precipitation. Analyses of these extreme events are required both for current and future climate conditions and solutions need to be developed to mitigate these effects. The analyses will be based on historical data, climate projections and hydrological modelling. Climate projections and hydrological modelling are subject to uncertainty, which need to be considered. The project can be focussed on urban or landscape problems either in Denmark or internationally.

Objectives

  • Hydrological modelling using either the MIKE SHE or MODFLOW-6 models based on historical data and climate projections.
  • Uncertainty related to climate and hydrological modelling.
  • Analysis of alternative mitigation solutions.

Contact person

Karsten H. Jensen (khj@geo.ku.dk) and Torben Sonnenborg (GEUS, tso@geus.dk)

24. Hydrogeologisk model for Storkøbenhavn

Geo har en meget detaljeret geologisk model (hydrostratigrafiske model) for Storkøbenhavn i 25×25 meter grid, som løbende bliver opdateret efterhånden, som ny viden kommer til fra f.eks.  anlægsprojekter og vandressourceopgaver. Modellen kan ses i GeoAtlasLive og den geologiske modellering foregår løbende i GeoScene3D.

Hovedformålet er at udbygge den hydrostratigrafiske model til en hydrogeologisk model via en række delopgaver og derefter anvende modellen til en konkret opgave.

Delopgaverne er:

  • at forbedre den hydrostratigrafiske model for de prækvartære lag ved hjælp af logstratigrafiske inddeling af kalken. Datagrundlaget skal baseres på geofysiske logs fra Gerda Databasen, samt indsamling af Geo’s mange geofysiske logs og flowlogs (Findes i Geo’s databaser, samt en del på vores projekt drev). Datagrundet øges herved betydeligt.
  • at udarbejde transmissivitetskort for kalken og evt. for sandmagasiner i Storkøbenhavn baseret på data og tolkninger af data fra Jupiter Databasen (autotolkning af Q/s data, tilbagepejlingsdata og udtræk af de ”få” transmissiviteter, som ligger direkte i Jupiter) samt samle data fra Geo’s mange pumpforsøg. Efter dataindsamling udføres geostatistik analyse af data og der optegnes et eller flere bud på transmissivitetskort, som senere kan indgår i den hydrologiske model.
  • at lave kort med fordeling af hydraulisk ledningsevner for de forskellige hydrostratigrafiske delinger i kalken baseret på borehulslogs, flowlogs og under hensyntagen til andre processer såsom glaciale påvirkninger og strukturelle forhold (forkastninger, foldninger etc.)
  • at opstille, kalibrere og anvende den eksisterende hydrologisk model (MIKE SHE) ved at inddrage resultaterne fra de forrige delopgaver. Modellen kan enten opstilles i MIKE SHE eller (GMS) MODFLOW og der skal være særlig fokus på grundvandsforholdene i kalken.

Det aftales nærmere hvilke(n) delopgave(r), som der skal lægges mest vægt på baseret på den studerendes ønsker. Der er også muligt at selv være med til at samle data ind i felten.

Formål

  • Dataindsamling fra forskellig kilder og kvaliteter
  • Logstratigrafiske analyse
  • Geostatistik analyse
  • Geologisk modellering GeoScene3D
  • Numerisk modellering i MIKE SHE eller MODFLOW

Contact persons

Flemming D. Christensen (Geo, fdc@geo.dk), Mia Haahr Saxtoft (Geo, mhs@geo.dk) og Jesper Lind (Geo, jel@geo.dk), og Søren Jessen (sj@ign.ku.dk)

25. Assessment of Solute Transport at the Field Scale to Safeguard Groundwater Resources

Pesticide leaching and its potential threat to groundwater reservoirs is a significant concern both in Denmark and globally. Recent media coverage has highlighted the relevance of this issue, underlining the urgency to address it (for more information in Danish, follow this link: https://www.dr.dk/nyheder/tema/sproejtegift-i-drikkevandet). Since 1999, the Danish Pesticide Leaching Program (PLAP) has monitored potential pesticide leaching across five field sites, with ongoing efforts by GEUS to gather and analyze hydrological and geochemical data using various methodologies.

Previous research has demonstrated significant disparities in pesticide leaching potential depending on the geological setting. For instance, fields situated in Quaternary moraine clay deposits may exhibit greater vulnerability compared to those in postglacial sandy deposits, attributed to fractures in clay facilitating faster pesticide transport (for more information in Danish, follow this link: https://www.dr.dk/nyheder/indland/grafik-saadan-kan-pesticider-komme-ned-i-grundvandet). Here, our objective is to assess leaching potential at the field scale in three dimensions by utilizing spatially distributed continuous monitoring data in numerical models. This approach represents a significant advancement in understanding and mitigating the risk of pesticide leaching in agricultural settings.

Objectives

  • Establish a local unstructured grid model implementing the knowledge of the geological depositions using MODFLOW.
  • Simulate flow and solute transport using MODLFOW.
  • Optimize the model using observation data
  • Compare the effectiveness of pesticide leaching assessment between the 3D model and conventional methods in pesticide regulatory procedures.

The thesis project will primarily involve modeling analysis using MODFLOW.

Contact persons

Sachin Karan (GEUS, saka@geus.dk) and Søren Jessen (sj@ign.ku.dk) 

26. Evaluating Groundwater-Surface Water Exchange through Varied Modeling Approaches

Regional groundwater models typically employ cell sizes on the order of hundreds of meters due to the vast areas they cover. Consequently, cells representing stream areas are also sized in the hundreds of meters, despite streams typically being only tens of meters wide at most. This discrepancy results in simulated groundwater fluxes to and from streams that may not accurately reflect reality, as the drainage areas near the streams are inadequately represented within the large cells occupied by the streams. Consequently, predictions made using such models concerning groundwater-surface water exchange, including both flow and solute transport, in scenarios such as climate or land use changes, may be unreliable.

In this thesis project, we aim to investigate the disparity in exchange fluxes by employing different conceptualizations to represent streams in regional groundwater models. The findings of this project will contribute to a better understanding of the optimal conceptualization of streams in regional groundwater modeling, facilitating more accurate simulations related to climate and land use changes. Candidates for this project should possess a strong interest in groundwater modeling, with proficiency in tools such as Python, GMS, or MIKE SHE, as well as experience in applying GIS for handling model inputs and outputs.

Objectives

  • Extract various areas from the DK-model and convert them into MODFLOW models.
  • Conceptualize these extracted areas within MODFLOW using both structured grid sizes (uniform cell size throughout the area) and unstructured grid sizes (variable cell sizes with smaller cells near streams).
  • Calibrate and compare the different conceptualizations in terms of parameters and simulated groundwater fluxes along streams.

Contact persons

Sachin Karan (GEUS, saka@geus.dk) and Søren Jessen (sj@ig.ku.dk)

27. Using Nitrate as a Tracer to Assess Groundwater Vulnerability

In the Danish Pesticide Leaching Program (PLAP), nitrate levels are routinely monitored alongside pesticides and their transformation products across five agricultural fields. While bromide has traditionally served as a tracer for model calibration in these fields, the potential of nitrate as a tracer remains unexplored. Hence, our objective is to analyze measured nitrate concentrations to discern nitrate leaching patterns across various agricultural fields representing diverse geological conditions. Additionally, we aim to integrate nitrate measurements into the calibration of 1D models representing these fields. Through this approach, we seek to enhance our understanding of how nitrate measurements can optimize model calibration and, ultimately, predict the risk of solute leaching into groundwater.

Objectives

  • Analyze time series of nitrate data from different fields representing varied geological conditions.
  • Prepare nitrate data for model calibration purposes.
  • Compare the outcomes of model calibration using nitrate with those obtained using bromide.

Contact persons

Sachin Karan (GEUS, saka@geus.dk), Rasmus Jakobsen (GEUS, raj@geus.dk) and Søren Jessen (sj@ig.ku.dk)

28. Utilizing Tracers to Quantify the Degree of Preferential Leaching during Rainfall Events

Rapid preferential flow through biopores and fractures is a well-documented phenomenon that significantly influences flow dynamics and solute transport to groundwater and surface water (for more information in Danish, follow this link: https://www.dr.dk/nyheder/indland/grafik-saadan-kan-pesticider-komme-ned-i-grundvandet). However, efficient methods for determining the size and distribution of fractures on a larger scale are currently lacking.

GEUS is actively involved in the ongoing Danish Pesticide Leaching Assessment Program (PLAP), which focuses on monitoring hydrological and geochemical data to evaluate the risk of pesticide leaching (http://plap.dk). Studies within PLAP have demonstrated that fractures within clayey tills may transport pesticides much faster than observed in sandy soils. Consequently, GEUS seeks to employ stable oxygen isotopes and analyze previously applied tracers to quantify preferential flow and assess its impact on pesticide transport.

Objectives

  • Set up a sampling campaign within a catchment containing one of the PLAP fields.
  • Install additional ISCO samplers to collect stream water for stable isotope analysis.
  • Analyze ongoing monitoring data from the PLAP field and collected data to estimate the contribution of fracture flow to drainage, streams, and groundwater.
  • If time permits, conceptualize findings through numerical model analysis and assess their effect on pesticide leaching.

The thesis project will primarily involve fieldwork and monitoring within a catchment containing one of the PLAP fields.

Contact persons

Sachin Karan (GEUS, saka@geus.dk) and Søren Jessen (sj@ign.ku.dk)

29. Effect of Groundwater Abstraction Near Stream Valleys

In many regions of Denmark, groundwater extraction for drinking water purposes occurs close to streams. With the increasing frequency of climate extremes such as flooding and drought, Danish water management faces challenges in ensuring sustainable groundwater abstraction for drinking purposes. Collaboratively, FORS A/S and GEUS are investigating the impact of groundwater abstraction near streams on flow dynamics and solute transport to and from the stream.

Current groundwater-stream exchange models often lack detailed resolution in stream valleys and adjacent areas, potentially leading to inaccurate estimations of the effects of groundwater abstraction on flow dynamics and solute transport. Furthermore, there is a gap in understanding the hydrological parameters governing groundwater-stream exchange.

Project Overview

In this project, we aim to establish a monitoring transect along the Ørbæk stream, where groundwater abstraction is occurring near the stream. The project offers opportunities for students interested in fieldwork, modeling, or a combination of both.

Objectives

  • Conduct measurements along the transect, including water table measurements, slug tests, groundwater sampling for stable oxygen isotope analysis, and stream flow measurements.
  • Develop a conceptual model for the established transect based on geological information and transect measurements.
  • Create a numerical transect model incorporating the transect measurements.
  • Estimate the hydrological parameters governing groundwater-stream exchange.

Contact persons

Bertel Nilsson (GEUS, bn@geus.dk), Sachin Karan (GEUS, saka@geus.dk) and Søren Jessen (sj@ign.ku.dk)

30. Maintaining Sustainable Groundwater Use under Changing Climate (1)

In Spain, the impacts of climate change are becoming increasingly evident, with more frequent extreme droughts and heightened stress on groundwater reserves. To ensure the sustainability of groundwater resources, novel technologies and strategies are imperative. One such approach is Managed Aquifer Recharge (MAR), which involves replenishing depleted groundwater aquifers by infiltrating water from various sources.

This thesis project focuses on southern Spain, where droughts and saltwater intrusion into coastal aquifers are on the rise. Collaborating with the University of Granada, Spain, we aim to investigate the potential of MAR to mitigate aquifer depletion using the state-of-the-art groundwater modeling code, MODFLOW 6. MODFLOW 6 is integrated into both GMS software and Python. While much of the data from the study area has been collected, there is potential for a field visit and collaboration with the University of Granada contingent upon funding availability.

Objectives

  • Develop a MODLFOW 6 model for the field site in Spain using the available data.
  • Calibrate the model based on field observations.
  • Explore the capabilities of MODFLOW 6 to simulate various MAR processes and structures.
  • Incorporate climate change projections and assess the MAR requirements to maintain a sustainable groundwater resource.
    • The thesis will primarily entail modeling based on the data gathered from the Spanish field site

Contact persons

Sachin Karan (GEUS, saka@geus.dk) and Søren Jessen (sj@ign.ku.dk)

31. Maintaining Sustainable Groundwater Use under Changing Climate (2)

In Spain, the ramifications of climate change are increasingly evident, with more frequent extreme droughts and heightened stress on groundwater reserves. Addressing these challenges requires innovative approaches and technologies. Managed Aquifer Recharge (MAR) emerges as a promising strategy, involving the infiltration of water from various sources into depleted groundwater aquifers. However, the feasibility of MAR hinges on the presence of suitable hydrogeological properties.

This thesis project focuses on southern Spain, where droughts and saltwater intrusion into coastal aquifers are escalating. Collaborating with the University of Granada, Spain, we aim to explore the MAR potential by utilizing heat as a tracer to investigate the properties of a proposed recharge site and the underlying groundwater aquifer. We will employ MODFLOW 6, a cutting-edge groundwater modeling code integrated into GMS software and Python, for our analysis.

Objectives

  • Develop a MODLFOW 6 model for a local field site in Spain using available data.
  • Calibrate the model against field observations.
  • Explore the capabilities of MODFLOW 6 in simulating heat transport within the groundwater
  • Re-calibrate the model using temperature observations from the field site.
  • Evaluate the field site and aquifer properties based on groundwater model analyses.
    • The thesis primarily entails modeling based on available data from the Spanish field site.

Contact persons

Sachin Karan (GEUS, saka@geus.dk) and Søren Jessen, (sj@ign.ku.dk)

32. Your project?

Please remember that the above MSc Thesis ideas are only ideas. You are always welcome to bring your own ideas to the table, and to discuss with us in order to develop the project that suits you best.

Contact persons

Majken Zibar (mcl@ign.ku.dk), Karsten Høgh Jensen (khj@ign.ku.dk) and Søren Jessen (sj@ign.ku.dk)