graduation research projects 2020

GRADUATION RESEARCH PROJECTS 2020

within the programme

EARTH SURFACE AND WATER

offered by the staff of the Department of Physical Geography

Faculty of Geosciences Utrecht University

Note that • some topics also fit in the programmes of “Earth Life and Climate” or “Marine Sciences” • additional ESW topics are available from the department of Earth Sciences, and • you can also bring in your own research topic.

2020 ESW Graduation Research Projects, 5 February 2020 MJ 2

OFFERED PROJECTS BY TRACK HYDR = Hydrology (Earth Surface and Water) CDFS = Coastal Dynamics and Fluvial Systems (Earth Surface and Water) GHEO = Geohazards and Earth Observation (Earth Surface and Water)

Hydrology Also in track(s)

p.

Impact of reservoir operation on river flow 5

Pathways and patterns in co-evolving hydrological system 6

Improving the local relevance of global hydrological models: case of the Blue Nile 7

Muddy waters: impact of global change on sediment sources and sinks along rivers 8

Real-time Asian Meteorological Observatory GHEO 9

Parallel algorithms for environmental modeling CDFS, GHEO 10

Formalizing interactions between environmental models CDFS, GHEO 11

Coupled field-agent modelling: an algebra for fields and objects CDFS, GHEO 12

Early-warning signals of desertification (or recovery) GHEO 13

Evaluating hydrograph and sedigraph characteristics as early-warning signals of soil degradation

GHEO 14

Identifying systemic change in catchment hydrology GHEO 15

Re-vegetation and water availability in Mediterranean areas: a study case in northeastern Spain

GHEO 16

Streamflow prediction under different re-vegetation scenarios GHEO 17

Personal exposure to air pollution in megacities of the world GHEO 18

Importance and vulnerability of the Indus Water Tower in Asia GHEO 19

Impacts of streamflow changes on concentrations of pharmaceuticals in rivers 20

Modelling trends in energy and manufacturing water uses 21

Modelling the hydrology of the African Rift Valley with PCR-GLOBWB2 GHEO 22

Mapping the global irrigation network: Linking surface water to irrigated areas 23

Evaluation of anthropogenic drivers to salinization of rivers and streams in the United States

24


HYDR = Hydrology (Earth Surface and Water) CDFS = Coastal Dynamics and Fluvial Systems (Earth Surface and Water) GHEO = Geohazards and Earth Observation (Earth Surface and Water)

Coastal Dynamics and Fluvial Systems Also in track(s)

p.

Development of estuaries under sea level rise 25

Building and raising land: Wisselpolders against sea level rise 26

Impact of sediment management strategies on deltas 27

Impact of sea-level rise on the Dutch coast 28

Machine learning to understand delta morphodynamics 29

The half-life of Lower Rhine Valley meanders: quantifying the self-reworking of meandering rivers

30

Calibrating the avulsion history of the Rhine-Meuse delta 31

Long-term morphological evolution of tide-influenced deltas 32

What causes the presence and dynamics of sawtooth bars? 33

Evolution of mega-nourishments on ebb-tidal deltas: the effect of sediment grain size

34

The effect of geological layers on morpho-dynamic evolution of tidal inlet systems in Delft3D

35

Numerical modelling of storm erosion at Egmond aan Zee GHEO 36

Detecting coastal change from satellite images GHEO 37

Embracing diversity: the role of intraspecific variation in dune formation 38

Repeated sand nourishments and nearshore evolution GHEO 39

Long-term suspended sediment dynamics in World Rivers HYDR 40

Suspended sediment characteristics in the Rhine River HYDR 41


HYDR = Hydrology (Earth Surface and Water) CDFS = Coastal Dynamics and Fluvial Systems (Earth Surface and Water) GHEO = Geohazards and Earth Observation (Earth Surface and Water)

Geohazards and Earth Observation Also in

track(s) p.

Structural and functional sediment connectivity in the Moroccan Atlas mountains HYDR 42

Satellite and UAV remote sensing of vegetation cover in coastal dunes CDFS 43

Unravelling bed erosion by debris flows with drone measurements in the Illgraben (Switzerland)

CDFS 44

Deciphering bed erosion by debris flows through physical scale experiments CDFS 45

Environmental Justice HYDR, CDFS 46

Downscaling Shared Socio-economic Pathways (SSPs) to improve projections of water demand in the high mountains of Asia

HYDR 47

Mapping intertidal topography and assessing mangrove colonization patterns in Suriname from UAV imagery

48

Vegetation development and Carbon sequestration in the Jordan Badia 49

Quantification of wind erosion and dust production in the Jordan Badia 50

Vegetation resilience and species composition changes in north Tanzania 51

Geomorphology and gully erosion in the Lake Manyara basin in northern Tanzania HYDR 52

Soil resources and water erosion risk in the Lake Manyara basin in northern Tanzania HYDR 53

Integrated modelling of fluvial futures CDFS 54

The rise and fall of riparian vegetation patches CDFS 55

Quantification of vegetation-erosion feedbacks on steep lateral moraine slopes in Turtmann Valley, Switzerland

CDFS 56

Remote sensing of a tidal flat, scaling from UAV mosaics to satellite time-series 57

Looking from the air below the surface of the Wadden Sea: using objects to map benthic macrofauna in UAV images

58


Earth Surface and Water Hydrology

Impact of reservoir operation on river flow

Supervision: Rens van Beek, Marc Bierkens, Michelle van Vliet

In cooperation with: Planbureau voor de Leefomgeving (PBL)

Description:

There are currently more than 30,000 large reservoirs in operation globally. These reservoirs serve several purposes (hydropower, water supply, flood control etc). The operation of those reservoirs typically 'flattens' the incoming hydrograph, which has a number of effects on river temperatures, and biogeochemical processes in the river stream. The operation rules of reservoirs itself generally depend on the main purpose of

the reservoir (hydropower, water supply, flood control etc), the variability of inflow, and a number of site-specific characteristics that are not know for most reservoirs globally. The objective of this study is to characterize the impacts of reservoir operation on continental and global scale discharge using a newly developed time varying data set of

reservoirs on a high spatial resolution and projected into the future.

Implemented in our hydrological model PCR-GLOBWB, the changing reservoir operations and their impacts on river discharge under present and future conditions can be assessed. This analysis can be expanded to cover also the potential of hydropower generation in the future. In detail, activities can comprise: • Collection of a set of observed inflow and release hydrographs of major reservoirs

from publicly available databases (~30-50 globally) to tune and validate the reservoir scheme.

• Characterization of reservoirs by inflow regime, purpose, residence time etc. • Quantification of reservoir impact on discharge at large scales using the global

hydrological model PCR-GLOBWB for contemporary conditions and into the future. The outcome of this project is of direct interest of the Netherlands Environmental Assessment Agency (PBL) with possible applications in the fields of aquatic biodiversity

and riverine nutrient transport.

Location: Utrecht University

Period: Autumn 2020 or earlier in mutual consent

Number of students: 1

Fits in track 1: Hydrology

Fits in track 2:

Prerequisites: Land Surface Hydrology, Hydrology and Climate/Fluvial Systems and Climate Change.

Contact / info: [email protected]

mailto:[email protected]




Pathways and patterns in co-evolving hydrological system

Supervision: Rens van Beek, Marc Bierkens

In cooperation with: -

Description:

Existing catchments reflect the close geohydroecological interactions in the patterns of soil, vegetation and topography that underlie the hydrological response. These patterns have evolved over long time scales resulting in landscapes that may be stable in light of (climate) variability and resilient in light of external disturbances. This implies that different pathways may have led to similar landscapes and that landscapes will adapt

differently to future changes. Understanding these principles is essential to evaluate the performance of existing hydrological models at the catchment scale and the transition of geohydroecological systems. The objective of this study is to identify key processes that affect the organization of a

landscape and to define and test different measures that may help to explain how these systems will adapt to changes imposed upon them. This will be done by means of

computer simulations and the evaluation of the results in terms of existing measures of landscape organization. These computer simulations can be performed with the meso-scale landscape dynamics model, CALEROS, which has been developed to simulate the interactions between climate, soil production and erosion, vegetation and land use on geomorphological to human time scales in Mediterranean environments. More in detail and in consultation with the student, activities will comprise: • Literature review of existing theories of landscape organization and optimization;

• Simulating the development of dynamically stable landscapes from similar but varying initial landscapes under stationary conditions;

• Quantification of the organization of landscape and energy, water and sediment flows in light of co-evolution and optimization;

• Classification of resulting stable landscapes and comparison with existing landscapes, either natural or human-impacted;

• Evaluation of shifts (trends, disturbance) and landscape adaptation in response to

change in terms of a landscape resilience.





Fits in track 2:

Prerequisites: Land Surface Hydrology, Land Surface Process Modelling






Improving the local relevance of global hydrological models: the case of the Blue Nile

Supervision: Rens van Beek, Marc Bierkens

In cooperation with:

Description:

Recently, global hydrological models –originally applied with a typical spatial resolution of 50 km- have been applied at increasingly finer scale. This increase in resolution is facilitated by technological improvements and by the need to obtain locally relevant data whilst maintaining consistency over larger scales (e.g., regional to continental);

thus, in light of past and future environmental change, shifts in hydrological regimes of areas can be assessed, areas compared, and potentially mitigating measures contemplated. Despite these recent advances, the application of global hydrological models at these fine scales is not clear-cut because of technological limitations, low-resolution meteorological datasets and structural model errors to capture fine-grained

hydrological processes. PCR-GLOBWB performs particularly poor for the Blue Nile, one of the focus areas of earth2observe, the agricultural heartland of Ethiopia and an

important contributor to the densely inhabited and irrigated lowlands of Sudan and Egypt. At present, we already apply the model at 10 km but we wish to develop it to 1km in this MSc project and understand the causes of the limited performance of PCR-GLOBWB in reproducing the hydrological regime correctly. Therefore, the tasks of this MSc project will include: • Parameterize PCR-GLOBWB at 1 km for the Blue Nile by downscaling the current

parameterization of our 10 km version: MOD1

• Improve the parameterization with locally available information (often from remote sensing): MOD1L

• Run the model with our current forcing (ERA-INTERIM) and with satellite based higher resolution rainfall products (e.g., TRMM)

• Compare the results of MOD1 and MOD1L with those from our 50-km model (MOD50) and 10 km model (MOD10).

• Validate the model against discharge data, remotely sensed evaporation and GRACE

gravity anomalies (groundwater). This information will then be used to understand which step leads to the largest improvement in model performance: 1) higher resolution, 2) better meteorological forcing; 3) including local information.





Fits in track 2:

Prerequisites: Land Surface Hydrology, Hydrology and Climate/Fluvial Systems and Climate Change.






Muddy waters: the impact of global change on sediment sources and sinks along rivers

Supervision: Rens van Beek, Hans Middelkoop


Description:

Rivers are crucial pathways along which water and sediment are transported. These fluxes are essential to man, having both beneficial (e.g., water availability, delta growth) as negative effects (e.g., siltation and pollution). At the same time, these fluxes change over time, not only as a result of natural trends and variability, but also as the

result of human-induced changes that affect the climate (GHG emissions) or the sediment supply (deforestation, trapping by reservoirs and river engineering). Such changes eventually have consequences for the long-term stability of river and delta systems. To sustainably manage these systems it is therefore crucial to know the provenance of sediment and to understand the impact of human interventions.

The objective of this study is to define the rate of change that affect river and delta

systems in relation to global change. Its outcome will help to bridge gaps in our present understanding of these systems and help to explain observed trends. To this end, this study will evaluate observational records over time in conjunction with model results and reconstructions. Specific topics that can be addressed during this study include: • Evaluation of the changing deposition of fine sediment behind weirs in light of the

observed decrease in suspended sediment for the River Rhine; • Assessment of any changes in sediment production along the River Rhine due to

reconstructed changes in land cover / land use and the observed sediment concentrations at gauging stations;

• Estimation of sediment volumes mobilized along the unstable river banks along large, monsoon-dominated rivers (Brahmaputra, Mekong or Amazon) using satellite

information on river course alterations, observed cross-sections and

empirical/mechanistic models.





Fits in track 2:

Prerequisites: Land Surface Hydrology, Land Surface Process Modelling

Contact / info: [email protected]; [email protected]



Real-time Asian Meteorological Observatory

Supervision: Prof. dr. W.W. Immerzeel

In cooperation with: Smartphones4Water

Description:

In 2019 the real-time Asian meteorological observatory (REAMO) (www.reamo.org) initiative was started by Utrecht University and the Nepal based organisation ICIMOD (www.icimod.org) and smartphones4water (www.smartphones4water.org). REAMO aspires to make meteorological data freely available and develop applications throughout (High Mountain) Asia by promoting and developing extensive networks of

weather stations from the plains to the mountains. To demonstrate the concept six weather stations measuring 12 variables are installed along an altitude transect from the Terai plains to the Himalaya. These data are transmitted via the mobile phone network and available in real-time with a 15-minute time step. These stations are operational since February 2020.

In this research that could be conducted by two students, you will design and develop

applications based on these data together with smartphones4water in Nepal. These applications can be related to raising climate change awareness, early warning for natural hazards, agriculture or hydropower for example. The objective is first to conceptualise and design different types of applications together by integrating the REAMO station data with remote sensing, publicly available data and models. Each student can subsequently select an application and further develop it together with smartphones4water. The goal is to develop an online web or mobile application for the

selected topic. A fieldtrip to Nepal is possible depending on project funding.

Location: Utrecht University / ICIMOD (Nepal)



Fits in track 1: Hydrology (HYDR)

Fits in track 2: Geohazards and earth observation (GHEO)

Prerequisites: Knowledge of GIS, Remote Sensing and spatial modelling


http://www.reamo.org/

http://www.reamo.org/

http://www.icimod.org/

http://www.icimod.org/

http://www.smartphones4water.org/

http://www.smartphones4water.org/





Parallel algorithms for environmental modeling¶

Supervision: Dr. Derek Karssenberg ([email protected]), Dr Oliver

Schmitz ([email protected]), Drs Kor de Jong ([email protected])


Description:

Algorithms for environmental modeling are at the heart of any raster-based environment model. The environmental modeller combines these core model building blocks to build a unique model. There are many different environmental modelling algorithms, some of which are also found in geographic information systems (GIS).

Until around 2005, CPU cores found in computers doubled in clock speed about every two years. Environmental modellers who wanted to use more complex modelling rules and/or larger data sets, just had to buy a new computer to decrease the increased model run times. That is not the case anymore and so model run times keep increasing with added model complexity and data.

Because CPU cores are not getting much faster anymore, hardware vendors have been adding additional CPU cores to their CPU’s. One obvious way to solve the issue of

increasing model run times is to make models use the multiple CPU cores. This requires a reimplementation of the above-mentioned environmental modelling algorithms. This project is about parallizing one or more environmental modelling algorithms. Some of these algorithms are very easy to parallize, and some are not. In this project you will look into parallizing one or more algorithms from the latter category. You will design one or more approaches to parallize the algorithm and, depending on your interest and background, test these approaches by implementing them.

This work is highly relevant, because the results may be used in a new implementation of our own library of modelling algorithms. Faster algorithms will have obvious benefits for the modellers and you can make a very concrete contribution to this. Supervision: You will be supervised by a team of experienced modellers and software engineers. They will provide you with a description of the sequential version of each algorithm and help you getting up to speed quickly. This team will at least consist of Dr.

Derek Karssenberg and Drs. Kor de Jong.


Period: To be determined

Number of students: 1-3

Track: Hydrology or Coastal dynamics and fluvial systems, or

Geohazards and Earth observation

Prerequisites: preferably courses in spatio-temporal modelling, geoinformatics, computer science

Contact / info: Derek Karssenberg ([email protected]), Kor de Jong

([email protected])

mailto:d.karssenberg%40uu.nl


mailto:o.schmitz%40uu.nl








Formalizing interactions between environmental models




Description:

Environmental modelling tools are today an important tool to construct spatio-temporal models. They outperform system programming languages as a model development environment regarding programming errors and implementation time and are therefore suitable for domain specialists like hydrologists, climatologists or ecologists.

Nevertheless, these tools have mostly focused on the syntax of modelling languages ignoring the semantic aspect of models, i.e. the meaning of the inputs, functions and outputs of a component model. Without a formal definition of the semantics of model components it is almost impossible to provide generic principles for coupling component models.

The coupling of specialized component models is certainly a requirement for the construction of integrated models, as these represent a more holistic view on

environmental processes. Therefore, the development of a formal definition of model components is required. A formal approach is provided by ontologies, which describe a conceptual domain, usually consisting of a set of statements that define concepts and relationships between concepts. While first steps towards ontologies for environmental models exist (e.g. Williams, M et al 2009, Lake, R.et al 2004) most of these approaches do not provide a complete description of all aspects of inputs and outputs. Research on the development of an ontology describing the whole domain of spatio-temporal models,

including various modelling paradigms, spatial domains, and application domains is still required. The research will be incorporated in an ongoing research project of integrated model development. Several research questions that are appropriate for a MSc thesis are available: • What is the current state of formal descriptions of model inputs and outputs, what

are limitations and potentials of those approaches

• Development (design and implementation) of or extension of an exisiting ontology suitable for coupling spatio-temporal model components

• Development (design and implementation) of a user interface for creating and modifying ontology descriptions by model developer

• Evaluating the possibilities of auto-generating ontology descriptions for existing models by software applications

• Assessing conversion problems of environmental variables occurring in the coupling of model components including different temporal and spatial resolutions, units, coverage, ...

Own proposals are welcome.




Track: Hydrology or Coastal dynamics and fluvial systems, or Geohazards and Earth observation

Prerequisites: courses in spatio-temporal modelling, geostatistics, remote

sensing, hydrology, geomorphology, and/or natural hazards (content of project can be adjusted to your background)

Contact / info: Derek Karssenberg ([email protected])











Coupled field-agent modelling: an algebra for fields and objects




Description:

In our view, a modelling language is a language for expressing environmental models, by modellers. Modellers are domain experts who are not necessarily knowledgeable or interested in software development. They need an environment with a high level of abstraction. A modelling language, like a script language or a graphical language for

example, provides the means for the domain expert to express his ideas about the phenomena being modelled. Most domain experts are not able to express such ideas in lower level languages like C++, C#, Java or even Python. The use of these languages require the domain expert to know things that are not directly related to expressing a model, like managing computer memory, managing files, handling errors. Another

reason to provide a modelling environment directly to the domain expert, instead of asking a software developer to develop models for the domain expert, is that important

decisions that have to be made during the development of the model get taken by the domain expert, instead of the developer. Like software development, model development is a highly iterative process, and decisions about the implementation need to be made continuously during the development of a model. Only for the most trivial models can the domain expert provide the software developer with the full specification of the model beforehand. In most cases the requirements of the model get adjusted continuously, based on the model’s performance.

Modellers mostly construct models along one of two modelling paradigms: field based or agent based. In the field based approach, phenomena are considered as spatially continuous, and spatial variation is represented by changes in the attribute value. Examples of fields are air temperature or elevation. In the agent based approach (also individual based, feature based, or object based approach), phenomena are represented as bounded objects that can be mobile. Spatial variation is represented by the

distribution of objects in space. Although many landscape systems require to combine

the field and agent based approaches, it is notably hard to do so in a model. This is mainly due to modelling languages being monolithic: they are either build around the field based or agent based paradigm. Integrating the two approaches requires coupling different modelling frameworks, which can be error prone, difficult, and time consuming. To overcome this problem, this study aims at developing a modelling language that integrates the two approaches. The envisioned language should provide functions that

operate on fields and/or agents, in a similar fashion. This will allow modellers to construct heterogeneous models consisting of agents and fields, in one single modelling language. Depending on your background, you can focus on designing concepts of such a language (e.g. the syntax), implementing a prototype (in your preferred programming language), or implementing a case study model that can be used to benchmark such a language. This is an interesting study if you like to combine your knowledge in spatio-temporal

modelling and computer science or GIS. It gives you the opportunity to work in a multi-disciplinary team consisting of environmental scientists and (PCRaster) software engineers.




Track: Hydrology or Coastal dynamics and fluvial systems, or Geohazards and Earth observation

Prerequisites: courses in spatio-temporal modelling, geostatistics, remote sensing, hydrology, geomorphology, and/or natural hazards

(content of project can be adjusted to your background)












Early-warning signals of desertification (or recovery)

Supervision: Dr Derek Karssenberg (Utrecht University)

In cooperation with: Researchers in Spain

Description:

Landscape systems may undergo abrupt transitions as a result of a gradual change in system drivers. Such regime shifts, or critical transitions, are often considered undesirable because they cause large changes in the landscape that are often irreversible. A well-known regime shift in land surface systems is desertification, i.e. the shift from a vegetated landscape to a largely unvegetated landscape, often with

degraded soils and increased erosion. The process of desertification is often abrupt, while it may be driven by a rather gradual increase in grazing intensity. At a certain threshold grazing intensity, biomass starts to decrease, which results in increased throughfall and runoff, causing increased runoff erosion, reducing soil thickness, which again has a negative effect on biomass growth. This positive feedback loop results in a

relatively abrupt degradation at the grazing intensity threshold. It is notably hard to detect this upcoming regime shift, because mean values of the

system state variables (e.g. soil thickness, discharge, vegetation biomass) show little change before a transition occurs. This problem has sparked research focused on finding alternative properties of the system that show a more marked change before a transition is coming. It has been shown that such so-called early-warning signals exist, more specifically higher-order statistics of state variables (e.g. instead of the mean value of discharge, the variance; instead of the mean vegetation biomass the spatial variation in biomass). Thus far, however, the existence of such early warning signals is

mainly shown for virtual realities, i.e. modelled hillslopes. The aim of this study is to investigate the existence of early-warning signals in the real-world. You will address the questions of 1) What are the statistical properties of vegetation cover, soil moisture and/or discharge of various catchments at different stages of soil degradation or soil recovery? 2) Can differences in statistical properties be explained by the occurrence of (or upcoming) system shifts?

You will answer these questions by a statistical analysis of time series of high-resolution

remote sensing data, including soil moisture, leaf area index and vegetation cover and possibly hydrographs for the same area. We have access to a data set in an area close to Zaragoza, Spain, and cooperation with the research group in Zaragoza is an option if you choose for this topic. Results of this analysis will be combined with information on the occurence of soil degradation or recovery in the same area, possibly by making a field visit. If time allows (or if the study is done by two students), the study can be

extended by a modelling study investigating the occurence of early-warning signals in similar, modelled, systems. Most of the data is already available.

Location: Utrecht University, possibility to visit Spain to collect additional

data



Track: Hydrology or Geohazards and Earth Observation

Prerequisites: courses in spatio-temporal modelling, geostatistics, remote sensing, hydrology, geomorphology, and/or natural hazards







Evaluating hydrograph and sedigraph characteristics as early-warning signals of soil degradation



Description:

Landscape systems my undergo abrupt transitions as a result of a gradual change in system drivers. Such regime shifts, or critical transitions, are often considered undesirable because they cause large changes in the landscape that are often irreversible. A well-known regime shift in land surface systems is the shift from thick

hillslope soils with high biomass to soils with almost no soil cover and low biomass. This process of land degradation is often abrupt, while it may be driven by a rather gradual increase in grazing intensity. At a certain threshold grazing intensity, biomass starts to decrease, which results in increased throughfall and runoff, causing increased runoff erosion, reducing soil thickness, which again has a negative effect on biomass growth.

This positive feedback loop results in a relatively abrupt degradation at the grazing intensity threshold.

It is notably hard to detect this upcoming regime shift, because mean values of the system state variables (e.g. soil thickness, discharge, vegetation biomass) show little change before a transition occurs. This problem has sparked research focused on finding alternative properties of the system that show a more marked change before a transition is coming. It has been shown that such so-called early-warning signals exist, more specifically higher-order statistics of state variables (e.g. instead of the mean value of discharge, the variance; instead of the mean vegetation biomass the spatial

variation in biomass). In this study you will evaluate whether statistical properties of hydrographs and/or sedigraphs can be used as early-warning signals for soil degradation. This is done in a modelling study. An existing hillslope evolution model that runs over time periods of hundreds to thousands of years is used to simulate the shift from a vegetated hillslope with thick soils to a degraded hillslope. Its main output is a timeseries of hillslope

geometries (topographical surface, development of gullies, regolith thickness) and

vegetation coverage. This output is used as input to an event-based hydrological model that is capable of modelling the complete hydrograph for individual events. It is expected that the hydrograph properties will change in advance of the upcoming shift towards a degraded system. To analyse, this, statistical properties (e.g. peakflow, time to peak, total discharge) will be calculated of hydrographs. This is an interesting topic if you like a fundamental approach to hydrology, with a focus

on modelling. The study is quite innovative, and you will be able to position your work in a (recently emerged) large body of literature on critical shifts and early-warning signals.




Track: Hydrology or Natural Hazards and Earth Observation

Prerequisites: courses in spatio-temporal modelling, hydrology, geomorphology, and/or natural hazards (content of project can be adjusted to your background)






Identifying systemic change in catchment hydrology



Description:

Temporal change in landscape systems is mostly studied with a focus on temporal variation in system states (e.g. groundwater level, discharge, denudation rate). These changes are driven by the landscape system, which includes all driving forces active in the landscape. In most cases, this system is considered constant, which implies that it is assumed that the processes and their interconnections remain the same. For instance,

model calibration against observational data (aiming at parameter identification) mostly assumes that the set of modelled processes and their associated parameters remain the same: a single set of equations and parameters is assumed to represent the past and future behavior of the system. In many cases, however, the system itself may change over time, due to external forces or due to internal mechanisms in the landscape that

completely alter the system processes and system behavior. An example is the land use system. Land use change is driven by many factors, including land prices, transport

costs, housing costs, environmental properties. In many cases, these factors are considered constant and land use change is modelled with the same set of rules for all time steps. In reality however, many of these factors may change due to implementation of new technology or environmental laws, which implies systemic change of the land use system. In this study you will address systemic change in the hydrological system. Hydrological models are nowadays-important tools for forecasting drought and flooding. To reduce

uncertainty in forecasts, these models are calibrated against observational data, in most cases river discharge time series. As noted above, it is mostly assumed that one unique set of model parameters can be used to represent hydrologic behavior for all time periods (both past and future simulations, for all years). In reality, however, systemic change will occur, which will be associated with changes in parameter values. Systemic change in catchment hydrology may be due to changes in land use (causing changes in

interception, infiltration), changes in geomorphology (causing changes in soil depth and

subsurface hydrology), or other changes such as implementation of new reservoirs. In this study you will identify these changes by an inverse method, by calibrating a catchment model separately for each time period (typically one year) in a series of time periods. This will result in a time series of parameter values (i.e., a value for each year), that represent the temporal change in the hydrologic system. Following this approach you can address the questions of 1) What is the temporal change in parameter values of

a catchment model? 2) Is it possible to relate these temporal changes to changes in the modelled catchment (e.g. landuse, geomorphology, reservoirs) that caused this systemic change in the hydrology? 3) What are the possible implications of this systemic change for forecasts of catchment discharge? For this study you will use existing calibration techniques on an existing data set (large time series data are available for multiple decennia) and model (one of the data sets available, most likely the Danube catchment). This is an interesting topic if you would

like to apply your knowledge in hydrology in a challenging rather innovative study. You will get technical support from staff and PhD students at our institute to get the calibrations running. The content of the study can be adjusted to your interests (e.g.

you could also study systemic change in other landscape systems).

Location: Utrecht University, possibility to cooperate with Münster University



Programme / track: Hydrology or Geohazards and Earth Observation

Prerequisites: courses in (stochastic) hydrology, spatio-temporal modelling







Re-vegetation and water availability in Mediterranean areas: a study case in northeastern Spain

Supervision: Derek Karssenberg ([email protected])

In cooperation with: Noemí Lana-Renault ([email protected])

Description:

In Mediterranean regions, water availability is low and depends on runoff generated in mountain areas. However, a marked decline in river discharges has been observed in the last century, related to i) decreasing precipitation and increasing temperature and ii) increasing expansion of vegetation in the headwaters due to land abandonment. On the

other hand, increasing water consumption for domestic, industrial and agricultural uses is occurring in the lowlands. Future water management will need to cope with these changing scenarios in order to ensure water supply. In this study we will focus on the impact of re-vegetation in the headwaters on future trends of water availability. Questions addressed include: how will re-vegetation affect

water availability? What is the seasonality of river flows? What is the water demand in the lowlands? What is the spatio-temporal pattern of the resulting water stress?

The research will be carried out in the Ebro basin, an example representative for large Mediterranean rivers. An existing process-based distributed hydrological model developed within the PCRaster Python framework and calibrated in a small catchment in the Pyrenees will be used. The model will be run under future land cover and climate change scenarios for a larger area in the Pyrenees. The discharge simulated in the upstream area will be compared to future downstream demand to calculate water stress.

Location: Utrecht University, possibility to visit the research area (Ebro basin) to collect additional data




Prerequisites: courses in spatio-temporal modelling, hydrology, geomorphology, and/or natural hazards

Contact / info: Noemí Lana-Renault ([email protected]) or

Derek Karssenberg ([email protected])



mailto:noemi-solange.lana-renault%40unirioja.es








Streamflow prediction under different re-vegetation scenarios

Supervision: Derek Karssenberg ([email protected])

In cooperation with: Noemí Lana-Renault ([email protected])

Description:

Mediterranean mountains have been largely affected by agricultural abandonment and subsequent vegetation recovery. The resulting expansion of forest and shrubs has modified the hydrological behavior of these areas, with significant impact on runoff production. Forecasting the effect on stream flow response of such vegetation recovery is particularly relevant in the Mediterranean region, where water resources are scarce

and uneven, and they rely on runoff generated in mountain areas. With this purpose, a process-based distributed hydrological model was developed within the PCRaster Python framework. The model has been calibrated in a past agricultural catchment (2.8 km2) in the Spanish Pyrenees, monitored by the Instituto Pirenacio de Ecologia (CSIC). In order to reproduce realistic vegetation recovery scenarios, we need

to determine the soil and vegetation parameters for several stages of land abandonment. The aim of this research is to characterize several stages of land

abandonment in terms of vegetation and soil properties, and to identify their effect on the stream flow response. The research will include: • Fieldwork in the study area (Spanish Pyrenees): at each site (representing a stage

of land abandonment) we will collect data related to vegetation and soil characteristics

• Statistical analysis of the field data • Simulation of the hydrological response of the catchment under different re-

vegetation scenarios, based on the data collected in the field Detailed content of the research can be discussed and tailored to your background. The fieldwork will take place preferably in September.

Location: Utrecht University, possibility to visit the research area (Ebro basin) to collect additional data




Prerequisites: courses in spatio-temporal modelling, hydrology, geomorphology, and/or natural hazards

Contact / info: Noemí Lana-Renault ([email protected]) or Derek Karssenberg ([email protected])











Personal exposure to air pollution in megacities of the world

Supervision: Dr Derek Karssenberg, Dr Oliver Schmitz

In cooperation with: Institute for Risk Assessment Sciences (Utrecht University)

Description:

Air pollution is one of the major concerns for human health. The effect of air pollution on health is often estimated using personal exposure to air pollution. This is the exposure to air pollution aggregated along the space-time path visited by an individual. An important question is how megacities in the world differ regarding personal exposure of their population. In this topic you will try to answer this question by calculating personal

exposure of the entire population of a number of megacities in the world, using publicly available information. Air pollution will be mapped by downscaling (increasing the level of detail) remotely sensed air pollution products to a spatial resolution of approximately 10 m using existing land use regression models, using open streetmap data as input. Space-time paths visited by individuals are estimated using location of houses, possibly

enriched with census data or other high-resolution information on location of dwellings. Then, air pollution is aggregated for these locations, for each individual in the

population. This results in distributions of personal exposure for the population of the city. The objective is to do this for a number of major cities in the world. This requires good skills in programming GIS operations, e.g. using Python and/or PCRaster, ArcGIS.

Location: Utrecht University, cooperation possible with Instititute for Risk Assessment Sciences, University Medical Centre Utrecht

Period: Any period is possible.

Number of students: 1-2 students


Prerequisites: Experience with programming (scripting, e.g. Python), background in GIS, spatio-temporal modelling, (geo-statistics).

Contact / info: Dr Derek Karssenberg, [email protected]



Importance and vulnerability of the Indus Water Tower in Asia

Supervision: Prof. dr. W.W. Immerzeel / dr. A.F. Lutz


Description:

Mountain regions are the water towers of the world. Recently a global assessment was conducted together with National Geographic, that assesses the importance and vulnerability of all mountain ranges in the world (https://www.nature.com/articles/s41586-019-1822-y). The importance is quantified through a so-called water tower index that integrates indices for the water supply

(precipitation, glaciers, snow, lakes) and demand (irrigation, cities, industry and nature). The vulnerability is subsequently quantified by accounting for climate change, hazards, population and socio-economic growth among others. The results of this study can be viewed at https://www.nationalgeographic.com/environment/perpetual-planet/.

This concept was developed at the global scale, but there is ample room to further improve and detail this approach at smaller scales. For this research topic the aim is to

implement the water tower index approach at smaller scales. Two basins are selected for this purpose, and the research can potentially also be conducted by a student couple, where each student focuses on a single basin. The first basin is the Trisuli basin in Nepal, where a lot of field research has been conducted in the past and the second basin is the Indus, which according to the global assessment is the most important water tower and where data will be available via the SustaIndus project (www.sustaindus.org).



Number of students: 1 or 2



Prerequisites: Knowledge of GIS, scripting, and spatial hydrological modelling

Contact / info: [email protected] / [email protected]

https://www.nature.com/articles/s41586-019-1822-y

https://www.nature.com/articles/s41586-019-1822-y

https://www.nationalgeographic.com/environment/perpetual-planet/

https://www.nationalgeographic.com/environment/perpetual-planet/

http://www.sustaindus.org/

http://www.sustaindus.org/





Impacts of streamflow changes on concentrations of pharmaceuticals in rivers

Supervision: Dr. Michelle van Vliet


Description:

Over the last decades the inputs of pharmaceuticals into rivers and lakes have increased drastically. This can adversely impact both environmental and human health, in particular in regions with limited wasted water treatment. Population growth and urbanization are expected to further increase the inputs of these chemicals into surface waters in several river basins across the globe. In addition, climate change and associated changes in

streamflow patterns and hydrological extremes (droughts, floods) will impact the concentrations of pharmaceuticals in rivers across the world and export to seas. This MSc thesis will focus on the impacts of streamflow changes and hydrological extremes on the concentrations of a number of pharmaceuticals in several river basins, including

the Rhine and Meuse basins. Observed concentration records for selected pharmaceuticals will be collected from online databases, and will be analysed in relation streamflow

changes and extremes events (e.g. drought). Based on the data-analyses and literature study, a simple model will be developed and tested on river basin level to simulate the river concentrations of the selected pharmaceuticals. In a next step, this model will be used to quantify the impacts of potential future changes in streamflow (under changing climate) and pollutant emissions on pharmaceutical concentrations.





Fits in track 2: -

Prerequisites: Affinity with data-analyses (e.g. in Excel, R) working with large datasets




Modelling trends in energy and manufacturing water uses

Supervision: Dr. Rens van Beek, Dr. Michelle van Vliet

In cooperation with: Not applicable

Description:

Both the energy and manufacturing sectors are major water users, especially in Europe and United States, where water withdrawals for these sectors currently contribute to about 50% of all surface water withdrawals (FAO-AQUASTAT, van Vliet et al, 2016). The PCR-

GLOBWB model (van Beek et al., 2011; Sutanudjaja et al., 2018) developed at Utrecht University simulates global gridded water resources availability and sectoral water use (industrial, irrigation, livestock, domestic sectors). As the energy and manufacturing are

currently considered as a single water use sector within the model, limited understanding exist on the separated contribution of energy and manufacturing to the increasing trends in sectoral water use and water scarcity. However, it is essential to make this subdivision as the nature of manufacturing and energy production are changing, partly in response

to anthropogenic climate change and socio-economic developments, and eventually arrive at more realistic scenarios on energy and water requirements.

This MSc thesis research will focus on trends in energy and manufacturing water use over the last decades based on analyses of reported data and simulations performed by the PCR-GLOBWB 2 global hydrological model. First, a conceptual model framework will be developed for energy and manufacturing water use, and an overview of reported sector water use data for countries globally will be made. In a next step, the student will adapt the source code of the industrial water use module of PCR-GLOBWB with the aim to

quantify the separated contribution from the energy and manufacturing sectors to the total sector water uses. The energy/manufacturing water use module will be validated against reported values for different regions and countries across the globe. In a next step, the student will quantify the contribution of both the energy and manufacturing sectors to water use developments over the last decades based analyses of the observed records and simulated series from PCR-GLOBWB 2.

References: Sutanudjaja, E. H., et al. (2018), PCR-GLOBWB 2: a 5 arcmin global hydrological and water resources model, Geosci. Model Dev., 11(6), 2429-2453, doi:10.5194/gmd-11-2429-2018. Van Beek, L. P. H., Y. Wada, and M. F. P. Bierkens (2011), Global monthly water stress: 1. Water balance and water availability, Water Resources Research, 47, doi:W0751710.1029/2010 wr009791. Van Vliet, M. T. H., D. Wiberg, S. Leduc, and K. Riahi (2016), Power-generation system vulnerability and adaptation to changes in climate and water resources, Nature Climate Change, 6(4), 375-380, http://dx.doi.org/10.1038/nclimate2903





Fits in track 2: -

Prerequisites: Affinity with programming and working with large datasets




Modelling the hydrology of the African Rift Valley with PCR-GLOBWB2

Supervision: Geert Sterk, Rens van Beek


Description:

The East African Rift System is one of the most extensive rifts on Earth, extending from Jordan in southwestern Asia southward through eastern Africa to Mozambique. The system is some 6400 km long and about 48–64 km wide. The system consists of two branches. The main branch, the Eastern Rift Valley (often called the Great Rift Valley, or Rift Valley), extends along the entire length of the system. In the north the rift is

occupied by the Jordan River, the Dead Sea, and the Gulf of Aqaba. It continues southward along the Red Sea and into the Ethiopian Denakil Plain to Lakes Rudolf (Turkana), Naivasha, and Magadi in Kenya. The rift is less obvious through Tanzania, because the eastern rim is much eroded, but it continues southward through the Shire River valley and Mozambique Plain to the coast of the Indian Ocean near Beira,

Mozambique. The western branch of the system, the Western Rift Valley, extends northward from the northern end of Lake Nyasa (Lake Malawi) in a great arc that

includes Lakes Rukwa, Tanganyika, Kivu, Edward, and Albert. The plateaus adjacent to the rift generally slope upward toward the valley and provide an average drop of from 600 to 900 m to the valley floor. The rift has been forming for some 30 million years and has been accompanied by extensive volcanism along parts of its length, producing such massifs as Kilimanjaro and Mount Kenya. There are many lakes in the African Rift Valley. Most of the lakes in the rift system are

deep and fjordlike, some with their floors well below sea level. Several problems exist with many lakes. Some seem to dry out (e.g. Lake Manyara) while others have experienced higher water levels in the recent past (e.g. Lake Awassa). Other problems are related to pollution and groundwater abstractions that have an impact on the hydrology. So far, not much is known about the fate of the available water resources.

The aim of this study is to quantify the hydrology of the African part of the Rift System.

Use will be made of remotely sensed hydro-meteorological data, available in-situ data and the global hydrological model PCR-GLOBWB2. The intention is to model the hydrology of the entire Rift System at fairly coarse scale, and carry out a more detailed modelling for two lakes: Lake Awassa in Ethiopia and Lake Manyara in Tanzania. The work will consist of 1) a literature review on the Rift Valley hydrology, 2) data collection from remote sensing and in-situ resources, 3) modelling the hydrology of the Rift Valley

with PCR-GLOBWB2, and 4) quantify the impacts of climate change scenario’s on the future of water resources in the Rift Valley System. This topic will be done at Utrecht, without any field work in Africa.

Location: Utrecht

Period: Sept. 2020 – Feb. 2021




Prerequisites: Hydrology, Modelling






Mapping the global irrigation network: Linking surface water to irrigated areas

Supervision: Menno Straatsma, Rens van Beek

In cooperation with: ---

Description:

Water scarcity presents a serious risk to people, industry, livestock and agriculture. The water gap, defined as the difference between water demand and water supply, is expected to increase due to changes in both the supply as well as demand. Climate change is expected to change the water supply with varying effects per basin, while water demand is largely affected by increased population and improved living standards.

Global Hydrological Models (GHMs) are regularly used in combination with water demand and supply routines to determine the water gap globally. Linking the water supply to water demand is normally carried out by a stepwise approach in which water is taken (1) from the river if a river is close by, (2) from a reservoir release upstream if present, and (3) from the non-sustainable ground water if the no surface water is

available. However, there is no physically-based link between surface water and irrigated areas, and water supply is not based on existing irrigation networks. Recently,

a GIS routine has been developed to extract efficient irrigation networks from a terrain model, but this needs to be extended and validated based on additional data. Building on current work at our department on global water scarcity, activities will comprise: • Develop a method to extract irrigation networks from OpenStreetMap together with

SRTM terrain heights. A topology needs to be built to link primary irrigation canals to

the main rivers, and secondary channels to the main channels. Development can be carried out on the Nile, Indus, San Joaquin, or Rhine irrigation systems.

• Parameterize and extend the existing GIS routine to extract irrigation networks from a DTM. Apply the improved GIS routine globally on a spatial resolution of 5 arc minutes (~10x10 km).

• Determine the effects of the irrigation network on consumptive use and water

scarcity using the PCR-GLOBWB global hydrological model. Compare the modelled

consumptive use against reported consumptive use.





Fits in track 2: -

Prerequisites: Land Surface Hydrology, Hydrology and Climate/Fluvial Systems and Climate Change. Recommended: Hands on GIS




Evaluation of anthropogenic drivers to salinization of rivers and streams in the United States

Supervision: Dr. Josefin Thorslund, Dr. Michelle van Vliet

In cooperation with: Not applicable

Description:

Salinization of rivers due to human activities, such as irrigation and application of de-icing road salts, is an increasing issue (e.g. Kaushal et al, 2018). Although some local studies have quantified the impact of human activities on freshwater salinity levels, limited understanding exists at the large (i.e. continental/global) scales. Improved understanding

of the relative impact of anthropogenic changes to freshwater salinity levels is critical for water resource management and future trajectories. This MSc thesis project focusses on estimating multiple human impacts (including irrigation, road salts for de-icing, impervious surface, dams and reservoirs and pesticide use) (Falcone et al, 2018) on salinity levels of rivers and streams across the US. The

student will compare salinity monitoring for river stations (using data from the Water Quality Portal/USGS) and calculations of evaporative enrichment (based on hydroclimatic

data and a mass balance approach) to identify in which river basins human impacts on river salinity levels are highest. Specifically, the mass balance approach will be used to quantify salt input to each river basin (from natural sources such as deposition and weathering), and compare this to salt output at the basin outlet (from river salinity and discharge data). From this, identification of basins with additional salt output compared to salt input, will be selected as having salt contributions from human activities. For these identified basins, the student will further analyse salinity changes in relation to quantified

changes in specified anthropogenic changes, to assess their potential relative contribution to observed river salinity trends. Falcone, James A., Jennifer C. Murphy, and Lori A. Sprague. “Regional Patterns of Anthropogenic Influences on Streams and Rivers in the Conterminous United States, from the Early 1970s to 2012.” Journal of Land Use Science 13, 6 (2018): 585–614. https://doi.org/10.1080/1747423X.2019.1590473 Kaushal, Sujay S., Gene E. Likens, Michael L. Pace, Ryan M. Utz, Shahan Haq, Julia Gorman, and Melissa Grese. “Freshwater Salinization Syndrome on a Continental Scale.” Proceedings of the National Academy of Sciences 115, no. 4 (2018): E574–83. https://doi.org/10.1073/pnas.1711234115.


Period: October 2020



Fits in track 2: -

Prerequisites: Affinity with data-analyses (e.g. in Excel, R) working with large datasets, GIS


https://doi.org/10.1073/pnas.1711234115

https://doi.org/10.1073/pnas.1711234115


Earth Surface and Water Coastal Dynamics and Fluvial Systems

Development of estuaries under sea level rise

Supervision: Jana Cox MSc., Steven Weisscher MSc., Prof. dr. Maarten

Kleinhans


Description:

Estuaries will face sea level rise in the coming decades, which will increase flood risk and will probably be detrimental to the rich biodiversity on the intertidal flats. This problem asks for a better understanding of the impact of sea level rise on such systems, which until now was mainly achieved via numerical modelling. Currently, we are able to

create entire estuaries in the lab in the tilting flume the Metronome and are eager to test how sea level rise affects dredged and natural estuaries with mud and vegetation. In this MSc project, you will conduct experiments in the Metronome to assess the impact of sea level rise on the development of dredged and natural estuaries. You will

analyse the morphological development using overhead imagery and digital elevation models, and compare your findings to already performed control experiments without

sea level rise. In addition, you may use one or more of the following tools to fit your interests: (1) GIS software to analyse overhead imagery; (2) the SyntheticStratigraphy tool with which you can make geological cross-sections and analyse e.g. preservation potential; (3) the flow model Nays2D to reproduce and study tidal flow over your DEMs, which also allows for creating tidal zonation maps (sub, inter, supra).

This subject is closely related to cutting-edge research themes of enthusiastic supervisors (see www.uu.nl/bruningslecture for videos and more information) and, as successfully done in the past, we aim for publication in a journal. There is plenty of space to fit the interests and ideas of the student.


Period: Flexible, with experiments starting in summer

Number of students: 1 or 2 or 3

Fits in track 1: Coastal dynamics and fluvial systems

Fits in track 2: Integrated stratigraphy and sedimentary systems (ELC)

Prerequisites: River and Delta Systems GEO4-4436 and/or Morphodynamics of Tidal Systems GEO4-4435


http://www.uu.nl/bruningslecture

http://www.uu.nl/bruningslecture







Building and raising land: Wisselpolders against sea level rise

Supervision: Steven Weisscher MSc., Marcio Boechat-Albernaz MSc., Prof. dr.

Maarten Kleinhans


Description:

Many estuaries have large harbours and intertidal flats and are therefore of high economic and ecological importance. However, these system services and the flood defences along estuaries are threatened by projected sea level rise in the coming decades. One solution that is currently debated to protect our land is the use of so-

called wisselpolders; polders that are given back to the estuary for a finite amount of time so they may capture sediments and raise above normal high tide water level, after which the polder is closed with a new dike. One such a polder that has not (yet?) been reclaimed is the Drowned Land of Saeftinghe in the Western Scheldt.

You will use the model Delft3D to model wisselpolders in an idealised or real estuary that includes mud and vegetation dynamics. Your challenge will be to determine (1) how

the location and size of the wisselpolder influence the tidal wave and the morphological development along the estuary, and/or (2) to what extent mud and vegetation speed up the land raise in the wisselpolder. Analyses of your Delft3D results are done in Matlab. This subject is closely related to cutting-edge research themes of enthusiastic supervisors and, as successfully done in the past, we aim for publication in a journal. There is plenty of space to fit the interests and ideas of the student.


Period: Any time after May 2020


Fits in track 1: Coastal dynamics and fluvial systems

Fits in track 2: -

Prerequisites: River and Delta Systems GEO4-4436 and/or Morphodynamics of Tidal Systems GEO4-4435






Impact of sediment management strategies on deltas

Supervision: Jaap Nienhuis, Jana Cox


Description:

In this project you will study different sediment management strategies implemented in different deltas globally. Strategies include dam building, building with nature, implementation of vegetation, dredging and dumping and others. The project will focus on two main aspects of these sediment management strategies: limitations to their implementation and their impact on sediment delivery to deltas.

The aim of the project is to understand future adaptation strategies for deltas which allow for a balance between socio-economic growth and sustainable growth of the delta i.e. sufficient sediment supply. The project will build on a pre-existing Google Earth Engine Database and future climate, sediment and socio-economic growth predictions.

The project will include expertise from members of the Water Climate and Future Delta Hub and is an opportunity to look at a problem with an interdisciplinary approach.

The project will look at a database of 47 deltas with a focus on the Rhine-Meuse, Mississippi, Amazon and Mekong deltas.


Period: Flexible


Fits in track 1: Coastal dynamics and fluvial systems (CDFS)

Fits in track 2: -

Prerequisites: Preferred but not required: GEO4-4403 Managing Future Deltas OR GEO4-4436 River and Delta Systems

Contact / info: [email protected] or [email protected]







Impact of sea-level rise on the Dutch coast

Supervision: Timothy Price, Jaap Nienhuis

In cooperation with: Various Dutch or US Universities, if interested

Description:

Sea-level rise is expected to have a major impact on our coastline. Theoretically, sea-level rise will lead to beach erosion because of increased offshore transport of beach sediments. Quantitative, physical evidence of this effect, however, are still lacking. We are looking for enthusiastic MSc students to apply this theory and predict future

coastal erosion along the Dutch coastline. You will learn about nearshore morphodynamics, climate change impacts, and get first-hand experience in several data analysis and numerical techniques.


Period: Flexible



Fits in track 2: -

Prerequisites: Preferred but not required: MATLAB/python, coastal morpho-

dynamics

Contact / info: [email protected] or [email protected]







Machine learning to understand delta morphodynamics

Supervision: Jaap Nienhuis

In cooperation with: Various Dutch or US universities, if interested

Description:

Recent advances in remote sensing have made it possible to investigate coastal and delta dynamics at a global scale. This has opened up opportunities to answer exciting new research questions. One of these questions concerns river delta area. River deltas vary in size, from small bay-head systems to mega deltas such as the Mississippi or the Mekong. Controls on delta size, however, are largely unquantified.

I am looking for an MSc student that is interested in learning about remote sensing and machine learning within the Google Earth Engine platform. With these tools you can design an algorithm to automatically detect delta area. Combined with a newly published dataset on ~11,000 river deltas we can start to answer cool new research

questions.


Period: Flexible


MSc programme: Earth Surface and Water


Fits in track 2: -

Prerequisites: Preferred but not required: Javascript/python, coastal/delta morphodynamics






The half-life of Lower Rhine Valley meanders: quantifying the self-reworking of meandering rivers

Supervision: Kim M. Cohen; Gilles Erkens; M.G. Kleinhans


Description:

The river Rhine between Bonn (Germany) and the Dutch border in the Holocene was a grant meandering river. The geological mapping and dating of the meander landscape is well developed. In this project we will use this mapping to investigate the efficiency of the meandering river in reworking its own bed: Middle Holocene meanders reworked the

point bars of Early Holocene meanders… what local volume of sediment was admixed to what volume of sediment upstream? Did the vertical sorting improve? Late Holocene meanders, in turn, reworked the Middle Holocene ones. Was the reworking of the same intensity or different? From reach to reach, were there differences in meander-reworking properties? Sediment trapped in point bars is stored for 100-1000s of years.

How do the volumes and lifetimes of bed sediment undergoing this fate compare to bed sediment taking part of the faster transport of bedforms in the river thalweg? What are

the exchange rates between thalweg transport and incorporation in long-lived bars? How different is this for meanders in the centre of the valley, compared to meanders at the edge of the system? Can we capture this all in some nice empiric exponential fit functions based on downstream and cross-valley location and time, and meaningful exponents similar to ‘half life’ for decay functions and ‘wavelength’ in cyclic functions? Understanding the half-life of meandering rivers could help us understand sediment

transport at 1000-10000 year time scales over larger distances of low land ‘between the edge of a basin’ (mountain foothills) and ‘the depocenter of the basin’ (e.g. the sea). The student will investigate questions such as those above starting from basic mapping, querying data, analysis in spreadsheet and basic geometric-linear models. No fieldwork, but opportunity of site visits.



Number of students: 1-2 (1: Rhine Bonn-Apex; 2: Meuse: Borgharen-Cuijk)


Fits in track 2: -

Prerequisites: Fluvial Morphodynamics (MSc); Introduction to GIS (at BSc or MSc level)




Calibrating the avulsion history of the Rhine-Meuse delta

Supervision: Kim Cohen; Esther Stouthamer


Description:

The geological-geomorphological mapping of former rivers of the Rhine-Meuse delta is very complete and so is its dating. However, data gathering has continued and it is 10 years since the mapping and incorporated avulsion history were last major updated. Our understanding of abandonment of large river branches has much improved. We now know that they took several centuries to silt up. Temporal overlap exists between newly

formed channels in their young stages and deceasing older channels in their abandonment stages. The dating evidence for stages of beginning river activity has grown and we now understand that avulsions have been triggered in multiple ways, location and setting and time-frame dependent. Amounts of dating evidence have grown too. Our database systems now allow to work and contribute to it over the web.

What rests to do is to combine all these loose altered insights in a redo of the avulsion-

history analysis: no longer longer equating ‘abandonment’ and ‘initiation’ or ‘crevassing’ and ‘mature’, but be more precise and distinct in categorizing and summarizing the moments when rivers began and stopped functioning. Perhaps we can go from two dated (one begin age, one end age) to four such dates: ‘begin initiation’, ‘begin maturity’, ‘begin abandonment’, ‘full abandonment’ for each system. We want to research if such values changed between transgression (<5000 cal yr) and high stand times (>5000), and between times with natural sediment loads (<3000) and those with

human increased ones (>3000 cal yr), as we now from sediment budget analysis – which we could also recalculate with an improved reconstruction. The interested student likes to visualise the delta branches network in maps and time-line and 14C histogram diagrams. The student likes to work with the established Rhine-Meuse delta database, and contribute to it and become an expert user. No fieldwork,

but opportunity of site visits.



Number of students: 1-2 (1: avulsion history; 2: sediment budgets)


Fits in track 2: -

Prerequisites: Introduction to GIS (at BSc or MSc level); Fluvial Morpho-dynamics (MSc);




Long-term morphological evolution of tide-influenced deltas

Supervision: Dr. Maarten van der Vegt

In cooperation with: Arya Iwantoro MSc

Description:

Deltas form the transition from river to the ocean and are forced by river discharge, tides and waves. Many deltas are undergoing large changes in their morphology because of deepening of fairways, construction of dams, changes in land-use etc. We need models to predict the evolution of these systems on decadal to centennial time scales. Often 2D or 3D models are used, but these are very time-consuming and only

few simulations can be performed. Recently we developed at UU a 1D model so simulate the morphological evolution of deltas. Using the model we showed that tides stabilize bifurcations in river deltas and also showed that shortcut channels tend to destabilize the morphology of deltas. However, the model still has a major shortcoming. The width of the channels has to be prescribed by the user and is not changing in time. In reality

width of channels will change when the morphology of channels develop. Eroding channel will widen, while channels that silt up will become narrower. In this project you

will add this effect to the existing code. Using the new code you will study how deltas will develop as a function of external hydrodynamic forcing and sediment supply. This can be done both for idealized geometries as for real cases. Furthermore, the effect of different human interventions in the system can be studied in a systematic way.

Location: e.g. Utrecht University

Period: e.g. Autumn 2020 or earlier in mutual consent



Fits in track 2: -

Prerequisites: List of required courses and/or experience






What causes the presence and dynamics of sawtooth bars?


In cooperation with: Name of external organisation

Description:

Sawtooth bars are shore-oblique bar patterns that can be found at the seaward side of the ebb-tidal deltas and barrier islands of almost all Dutch and German tidal inlet systems (see Fig 1 for an example). Although they are abundant we have no idea what drives their morphological evolution. Recently we have made an inventory of their occurrence and typical dimensions. We found that they can be a few meters high, have

wave lengths between 400 and 900 m, migrate up to 80 m/year and have a typical growth and decay time scale of several years. The main question is: what is the generation mechanism of these bars and what explains the typical characteristics? We will use a model approach to study the generation of these sawtooth bars. Starting

from an alongshore uniform bed, we add small sawtooth bars as perturbations and study whether these perturbations can grow, decay or migrate in time. The

perturbations that grow fastest should explain the characteristics as we observe in the field. Subsequently we can study the sawtooth bar characteristics as a function of tidal range, wave height, orientation with respect to ebb-tidal delta etc.

Figure 1. Example of sawtooth bars occurring at the ebb-tidal delta of the Frisian Inlet.

The bars are visible as the repetitive pattern of shore-oblique crests and troughs along the ebb-tidal delta and island of Schiermonnikoog.





Fits in track 2: -

Prerequisites: Morphodynamics of tidal systems, morphodynamics of wave-

dominated coasts






Evolution of mega-nourishments on ebb-tidal deltas: the effect of sediment grain size


In cooperation with: Klaas Lenstra MSc (Arcadis)

Description:

Mega-nourishments on ebb-tidal deltas have been proposed (like the Sand Motor). These should mitigate negative effects of sea-level rise and human interventions, which have caused a sediment deficit in the Wadden Sea. Observations show that many ebb-tidal deltas of the Dutch Wadden Sea are eroding and it has been suggested that the

eroded sediment was deposited in the Wadden Sea. With accelerating sea-level rise more sediment is needed in the Wadden Sea to keep the intertidal areas and this sediment could be delivered by nourishments at ebb-tidal deltas. First tests with an idealized model set-up in Delft3D showed that such an approach might work, but that it also depends on the location of the nourishment and the timing with respect to the

cyclic behaviour. There are some intriguing questions that still need to be addressed. For example, the sediments of the ebb-tidal delta are relatively coarse, while the

sediments that have been imported into the Wadden Sea are much finer. How to link the erosion of the ebb-tidal delta to the sediment imported into the Wadden Sea? Model studies on the long-term effects of nourishment only had one grain size and the sensitivity of results to sediment grain size was not studied yet. This is an important aspect, because it has been shown that different sediment fractions have very distinctive sediment transport pathways and mechanisms. In this project you will study the effects of different grain sizes on the morphological evolution of ebb-tidal deltas.

Furthermore, you will study how the different sediment fractions will be transported, and how nourishments influence these processes.





Fits in track 2: -

Prerequisites: Morphodynamics of tidal systems






The effect of geological layers on morpho-dynamic evolution of tidal inlet systems in Delft3D


In cooperation with: Dr. Marc Hijma and Dr. Helena van der Vegt (Deltares)

Description:

In the Netherlands, as in many other countries, coastal zone managers need to understand coastal evolution in the near future (< 5 years) as well as on longer time scales (5-25 yrs) while also accounting for on longer-term evolution (25-100yrs). Coastal evolution on these time scales is not only influenced by hydrodynamics

conditions and sediment dynamics, but for a large part also by the build-up of the subsurface. In the Netherlands, the relevant subsurface consists for a large part of different types of sand, but at several places also of erosion-resistant layers like glacial till, stiff clays and peat. This results in spatial variation in the erodibility of the deposits which has an influence on coastal evolution.

To date, limited work has been done to incorporate the influence of geology on coastal evolution in models like Delft3D. In 2019 a conceptual model of effect of erosion-

resistant layers was developed and it was tested with Delft3D simulations. To improve our understanding of the balance between the sediment dynamics and geological parameterization, comparison between simulation results and observed morphodynamics surrounding the Ameland inlet can be employed. This requires simulations to more closely approximate the Ameland tidal-inlet system. Questions that can be addressed are: How does the importance of parameterization of the erosion-resistant geological layer compare to the importance of sediment supply from outside

the tidal basin in the formation of a secondary channel? What is the relative importance of the initial sediment distribution compared to the parameterization of the erosion resistant geological layer in the depth variation of the main channel? The project will be executed partly at Deltares.





Fits in track 2: -

Prerequisites: River and delta systems, Morphodyamics of tidal systems






Numerical modelling of storm erosion at Egmond aan Zee

Supervision: Timothy Price, Bart Grasmeijer, Gerben Ruessink

In cooperation with: Ellen Quataert (Deltares)

Description:

Along wave-dominated coasts, sandy beach-dune systems can erode severely during storms. On the Dutch coast, dune erosion is most common during heavy storms from the north-west, characterised by large waves and high surge levels. Surprisingly, dune erosion volumes may vary alongshore over distances as little as 500 m. It is thought that this alongshore variation in erosion results from pre-storm differences in dune

properties and the presence of embryo dunes in particular. The alongshore dune-erosion variability may also result from depth variations in the nearshore sandbar, which allow larger (smaller) waves to reach the dune at deeper (shallower) sections of the bar. It is unknown how wave attack varies alongshore during storms on the Dutch coast, mainly due to the difficulties involved in obtaining measurements during harsh storm

conditions.

This project provides an opportunity for a student to work on erosion of a beach-dune system, using the numerical model XBeach. This model was developed specifically to simulate the impact of extreme storms on sandy coasts. The student will apply the model to reproduce a number of different storms captured by field measurements. A data set of waves, and pre- and post-storm bed levels obtained at Egmond aan Zee during different storms is available for setting up the model, and to assess model agreement. The objective of this project is to reproduce and study the alongshore

variability in hydrodynamics and morphological change during different storms, from the surf zone up to the dune. This includes the analysis of wave energy spectra (short waves and infragravity waves), in relation to the nearshore bathymetry and offshore buoy data. The model-data combination will provide new insights into the alongshore variations in wave conditions during storms on the Dutch coast.

Depending on occurrence of storm conditions during the thesis period, you will have the

possibility to spend several days in the field to perform measurements. This topic requires a background in coastal dynamics and good programming skills (in Matlab) are a must.

Location: Desk study, with the possibility of a field visit





Prerequisites: GEO4-4434 Morphodynamics of wave-dominated coasts

Contact / info: Timothy Price; [email protected]



Detecting coastal change from satellite images

Supervision: Timothy Price, Gerben Ruessink


Description:

Sandy coastlines constantly change in response to variations in waves, storm surges, mean sea levels and human impacts. The resulting morphological changes, however, may vary along an entire coastline through time, depending on the orientation of the coastline, the presence of tidal inlets and coastal management strategies. Monitoring coastal change through in-situ measurements remains a challenging and costly task

(both in terms of money and time). Previous studies have shown that shoreline positions are suitable indicators for analysing changes in coastal morphology. Over the past 5-10 years, publically available satellite images (e.g. from Landsat and Sentinel-2) have increasingly been used to detect changes in shoreline positions. These images provide a low-cost solution to obtain long-term, high-resolution observations of coastal

change over the last three decades at many sites worldwide.

This project provides the opportunity to work with satellite data to study and compare shoreline development at various locations along the Dutch coast. For this, the open-source software toolkit CoastSat will be used (https://github.com/kvos/CoastSat). This toolkit assists a (non-expert) user in the retrieval of satellite images from Google earth Engine and the extraction of shorelines from these images. The objective of this project is (1) to assess the applicability of CoastSat on the Dutch coast and (2) to compare the shoreline response at contrasting sites. Potential locations include the tip of a barrier

island (Wadden Sea), a mega-nourishment (Hondsbossche-Pettemer Zeeduin), a former ebb-delta and the adjacent coast (Bollen van de Ooster), and a straight stretch of the Holland coast. Existing datasets of bathymetric measurements are available for the assessment of the technique, and measured offshore wave conditions and water levels for the analysis of the shoreline behaviour.

This topic requires a background in coastal dynamics OR remote sensing and a keen

interest for programming (in Python) is a must.

Location: Desk study






Contact / info: Timothy Price; [email protected]

https://github.com/kvos/CoastSat

https://github.com/kvos/CoastSat





Embracing diversity: the role of intraspecific variation in dune formation

Supervision: Valérie Reijers (NIOZ)

In cooperation with: Gerben Ruessink

Description:

Vegetated coastal ecosystems such as coastal dunes, salt marshes and seagrass meadows are often formed and dominated by a single landscape-forming species. While recent studies have demonstrated the importance of between-species variation in engineering traits for landscape formation, variation between individuals of the same species is often neglected. However, an increasing number of ecological studies have

shown that intraspecific variation can be equally important for ecosystem functioning and evolutionary processes. Especially in these mono-specific coastal landscapes, we expect that intraspecific variation can have important consequences for ecosystem functioning and resilience under global change.

In this MSc research there is room for two students to study the role of intraspecific variation in coastal dune landscapes. One topic will be focussed on population trait

variability in a more natural (expected high genetic diversity) vs. a restored dune landscape (expected low genetic diversity). The importance of trait variability on the performance and engineering ability of dune grasses will be tested using manipulative experiments in a natural setting. Another topic will investigate to what extent the environmental conditions affect engineering trait expression and survival in dune grasses. While most restoration projects are carried out using transplants from the same genetic background, it is unknown how this affects restoration success depending

on environmental conditions. In this project the student will set up a fieldexperiment over a biogeomorphic dune gradient using transplants from different origins to assess the relative importance of environmental settings and genetic background on dune grass performance. These topics are suited for MSc students with a strong interest in coastal dunes, plant

physiology and biogeochemistry. Both students are expected to work closely together

and to spend considerable time in the field and the lab. This MSc Research can be carried out in 37.5 or 45 ECTS.

Location: NIOZ Texel; Coastal Systems Dept. Possible fieldwork locations:

Texel and Oostvoorne

Period: Start period 4 (2020)


MSc programme: Earth Surface and Water/ Marine Sciences

Prerequisites: GEO4-1450 Coastal Ecology




Repeated sand nourishments and nearshore evolution

Supervision: Gerben Ruessink

In cooperation with: Timothy Price

Description:

Since the early 1990s sand nourishments have become common practice in Dutch coastal zone management to combat structural coastal erosion. Nowadays, about 10 to 15 million m3 of sand is nourished annually on the Dutch coast, most of which as shoreface nourishments, that is, in water depths of 3 to 8 m. While we have a reasonable understanding of how an individual shoreface nourishment temporarily

affects the evolution of nearshore morphology, it is not understood how repeated nourishments affect the long-term dynamics of the nearshore zone. For example, how do repeated nourishments affect the presence, size and long-term migration of sandbars? Do they result in persistent changes in the number of rip channels? Do the repeated nourishments lead to a systematic increase in beach width and hence volume

of the foredune? Do the nourishments alter large-scale variability in sandbars, such as bifurcations, switches and coupling? Questions like these are central to this MSc project.

The overarching aim is to quantify how repeated nourishments affect the long-term dynamics of nearshore morphology, including subtidal sandbars, the intertidal beach and the foredune. The case study in the project will be Noordwijk aan Zee, where the first shoreface nourishment was implemented in 1998. The data set you can work with comprises annual depth surveys (the Jarkus database) dating back to 1965 and hourly/daily video images from an Argus station available since 1995. Both data sets

thus date back to before the first nourishment. Extensive time series of water levels, waves and wind are available too. The topic is suited for an MSc student with a background in coastal dynamics and a keen interest in data analysis, remote sensing and coastal zone management. The MSc can be carried out in 37.5 or 45 ECTS. Familiarity with Matlab programming is a pre.

Depending on progress you will have to opportunity to present your results to the Dutch

coastal community during the research days of the Dutch centre for Coastal Research (NCK) in 2021.


Period: Start in period 4 or after summer in period 1








Long-term suspended sediment dynamics in World Rivers

Supervision: Dr. Marcel van der Perk


Description:

This desk study aims to identify the mechanisms behind the decline in the suspended sediment loads that has been observed in many river basins around the globe. Based on existing data sets of long-term measured discharge and suspended sediment concentrations, a thorough data analysis will be carried out, including the fitting rating curve parameters and mass curve analysis. The obtained results will provide improved

insight and knowledge about the hydrologic controls of suspended sediment transfer through river basins and about the natural and human-induced changes in these controls that have taken place during the past decades.






Prerequisites: GEO4-4436 River and Delta Systems; GEO4- 4412 Statistics and

Data Analysis in Physical Geography (preferred)




Suspended sediment characteristics in the Rhine River

Supervision: Dr Marcel van der Perk


Description:

Sediment characteristics, such particle size distribution, organic matter content, settling

velocity distribution, control for a large part the transport and fate of suspended

sediments in river systems. Furthermore, their chemical composition can reveal the

origin of the sediment. However, data on these sediment characteristics is scarce for

most large rivers, including the Dutch rivers. This study aims to determine the sediment

characteristics and their spatial and temporal variability in the Rhine River. This

information will be used to assess the origin, transport pathways, and fate of suspended

sediment in the Rhine River.

Location: Rhine River, The Netherlands and/or Germany

Period: from September 2020




Prerequisites: GEO4-4436 River and Delta Systems



Earth Surface and Water Geohazards and Earth Observation

Structural and functional sediment connectivity in the Moroccan Atlas mountains

Supervision: Ángeles G. Mayor & Jerry van Dijk, (Copernicus Inst.-Environmental Sciences); Steven M.de Jong (PG)

In cooperation with: UU GEO Copernicus & Physical Geography

Description:

This MSc thesis proposal is framed on a recently-started project about the potential of using a connectivity-based approach to integrate geomorphological, ecological and social networks in the study of food-related transitions in subsistence communities of

dryland mountains. Land degradation in these systems, caused by the interaction between unsustainable land management and climate change (e.g., torrential rainfalls causing fast floods), is severely damaging the livelihoods and food security of billions of people worldwide. The study area is in the Ounila catchment (High Atlas mountains, Morocco) where a shift from nomadic to sedentary livestock farming has caused

overgrazing and the associated degradation of rangelands and their food resources, as well as the loss of social cohesion. This MSc thesis will contribute to defining the

geomorphological network of the Ounila catchment by assessing the structural and functional sediment connectivity. The master thesis will include desk work and a field visit in spring 2020 (or autumn 2020 as latest) to the study area in Morocco. Before the field visit, the student will gather and analyse GIS data (e.g., topography, land cover, etc.) in order to assess the structural sediment connectivity and, if possible, changes in this connectivity over time. The field visit will focus on ground-truthing the structural connectivity and collecting sediment samples to analyse their provenance in order to

assess the functional sediment connectivity. Ideally, the student should start the thesis as soon as possible (and July as latest). The student will collaborate with other MSc students that focus on the social and ecological networks. The student will be co-supervised by Ángeles G. Mayor (Copernicus Institute of Sustainable Development, UU).


Period: As early as possible (the seed-money project ends in Dec 2020)




Prerequisites: Two of three: Remote sensing; Hazards & Risk Assessment; Land surface modelling.

Contact / info: [email protected]; [email protected]; [email protected]









Satellite and UAV remote sensing of vegetation cover in coastal dunes

Supervision: Gerben Ruessink

In cooperation with: Wiebe Nijland

Description:

Vegetation mapping is among the most common and important uses of satellite images. Nonetheless, such mapping is not straightforward for landscapes with sparse vegetation, comprising plant patches that are below the spatial resolution of the satellite image. In such heterogeneous landscapes a pixel contains a mixture of multiple features, such as vegetation and bare ground. Several techniques have been designed to “unmix” the

total signal into the separate contributions; the vegetation product of unmixing is a map of fractional vegetation cover, i.e., for each pixel the fraction of vegetation inside that pixel is provided. The accuracy of fractional vegetation cover maps is often poorly known as collecting sufficient ground control information through field surveys is very time consuming. This limitation may be overcome with the use of repeated ultra-high

resolution (0.05 x 0.05 m) orthomosaics acquired with an Unmanned Aerial Vehicle (UAV, or drone) in a spatially extensive area, but this has not yet been explored

systematically. Coastal dunes are a prime example of a spatially heterogeneous landscape. On top of that, there is substantial temporal dynamics in vegetation cover, for example, in response to severe storms, seasonal variations in the plant growth cycle, and on longer time scales due to the dunes geomorphological evolution. The rapid increase in the number of available satellite images, together with knowledge on the accuracy of

vegetation cover maps, is expected to lead to a breakthrough in our understanding how coastal dunes evolve as a bio-geomorphological system. The aim of this MSc project is twofold: (1) to quantify the accuracy of satellite-derived vegetation cover maps with ultra-high resolution UAV orthomosaics, and (2) to evaluate the capability of different satellite platforms to capture vegetation dynamics in coastal

dunes. You will focus on a site near Bloemendaal aan Zee, for which several UAV

orthomosaics already exist as part of an ongoing monitoring programme. Also, you will have the opportunity to assist in the collection and processing of new UAV orthomosaics during your MSc work. You can use images from various satellites with different spatial resolution, including Planetscope, Sentinel-2, TripleSat and Worldview-1. This will illustrate how the performance of unmixing depends on the resolution of the satellite images, and will provide insight into what temporal and spatial aspects of vegetation

dynamics can actually be quantified from the images. The topic is suited for an MSc student with a background in remote sensing and a keen interest in data analysis and, preferably, coastal landscapes. The MSc project can be carried out in 37.5 or 45 ECTS.


Period: Start in period 4 or after summer in period 1




Prerequisites: GEO4-4408 Remote Sensing




Unravelling bed erosion by debris flows with drone measurements in the Illgraben (Switzerland)

Supervision: Dr. Tjalling de Haas, Dr. Wiebe Nijland

In cooperation with: Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)

Description:

Debris flows are masses of soil, rock and water that rush down mountainsides and spill onto valley floors, where they can annihilate thousands of people and wreck property. Debris flows may grow greatly in size and hazardous potential by eroding bed material.

To minimize debris-flow hazards, the presently unknown mechanisms of debris-flow erosion thus urgently need to be unravelled. The goal of this project is to unravel and quantify the mechanisms underlying bed erosion by debris flows. To reach this goal, the student will collect drone imagery of the

channel bed in the Illgraben torrent in the Swiss Alps (46°17'45.67"N, 7°38'4.12"E), and create pre- and post-debris-flow elevation models of the channel bed. The Illgraben

torrent is the most active debris-flow channel in Europe generating multiple flows each summer. The Swiss Federal Institute for Forest, Snow and Landscape Research operates a measurement station in the channel measuring key flow properties, such as velocity, depth, and density. The student will compare erosion volumes extracted from the elevation models to measured flow properties to unravel which flow properties control bed erosion in debris flows.

This project builds on the main lines of research of the supervisor as part of the NWO-VENI grant of Dr. Tjalling de Haas. Therefore, the results will likely be used in peer-reviewed journal article(s), on which the student will be one of the authors.

Location: Field measurements in at Illgraben (Leuk, Switzerland) Data analysis at Utrecht University

Period: Fieldwork July/August, and analysis subsequently




Prerequisites: -




Deciphering bed erosion by debris flows through physical scale experiments

Supervision: Dr. Tjalling de Haas

In cooperation with: Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)

Description:

Debris flows are masses of soil, rock and water that rush down mountainsides and spill onto valley floors, where they can annihilate thousands of people and wreck property. Expansion of human population into mountainous regions and the effects of global warming have increased the hazardous effects of debris flows over the last decades.

Debris flows may grow greatly in size and hazardous potential by eroding bed material. To minimize debris-flow hazards, the mechanisms of debris-flow erosion thus urgently need to be unravelled. Limited field and experimental data suggest that debris flows may entrain bed material by 1) basal-shear forces, by material sliding along the bed

surface; and 2) impact forces, by rocks hitting the bed. Yet, how these forces vary between flows and affect bed erosion is poorly understood.

The goal of this project is to experimentally unravel and quantify the mechanisms underlying bed erosion by debris flows. To reach this goal, the student will perform a comprehensive set of experiments in a brand new, 6 m long and 5 m high, debris-flow flume in the Earth Simulation Lab, equipped with state-of-the-art measurement equipment including load cell, geophones and laser scanners.

This project builds on the main lines of research of the supervisor as part of the NWO-VENI grant of Dr. Tjalling de Haas. Therefore, the results will likely be used in peer-reviewed journal article(s), on which the student will be one of the authors.


Period: -




Prerequisites: -




Environmental Justice


In cooperation with: Julius Centre, UMCU and with team members of the Global Geo Health Data Center (http://www.gghdc.nl).

Description:

Human exposure to our environment has considerable effects on human health. The spatial distribution of human exposures to environmental variables such as air pollution, urban green, noise and fast-food restaurants, is believed to reflect differences in income, ethnicity, unemployment and education-levels. This study aims to explore the

patterns of the environmental exposures across the Netherlands and identify relations with the neighbourhood deprivation (income, ethnicity, unemployment and education-levels). The results of this study would have implications in restoring environmental justice and consequently reduce health inequalities amongst different socio-economic groups. The thesis will include implementation of human exposure assessment

techniques to be applied across the Dutch population and methods to compare spatial patterns in human exposure and neighbourhood deprivation.




Track: Geohazards and Earth Observation but other tracks may also fit.

Prerequisites: Courses in geographical information science and statistics is a requirement. Preferably basic knowledge in scripting (programming), remote sensing and/or simulation modelling (content of project can be adjusted to your background).

Contact / info: Derek Karssenberg ([email protected]), Anna-Maria Ntarladima ([email protected])







Downscaling Shared Socio-economic Pathways (SSPs) to improve projections of water demand in the high mountains of Asia

Supervision: Dr. Philip Kraaijenbrink, Prof. dr. Walter Immerzeel


Description:

During this century we expect climate change to continue, which will impact water supply to rivers as weather patterns and land surfaces change. In the high mountain regions of Asia this may be particularly impactful, since river runoff that comes from its vast ice reserves (e.g. glaciers, permafrost) and seasonal snow may change

dramatically under a warming climate, impacting (seasonal) water supply to the densely populated downstream areas. To determine how much water is available in the future, it is however crucial to also understand how water demand will change. This largely depends on socio-economic factors such as increasing prosperity and population growth, as well as technological advances. Future scenarios of socio-economic change on a

global scale are available in the form of Shared Socio-economic Pathways (SSPs), which prescribe specific future changes in for example national population, urbanization and

per capita GDP. These scenarios are coarse, however, and to properly integrate SSPs in regional water balance models more detail is required. In this project you will use auxiliary datasets and socio-economic concepts to downscale SSPs to higher resolution gridded information using spatiotemporal modelling techniques for specific regions in Asia. Outputs are for example population (growth), urbanization, land use change, and resulting changes in water demand. Results could be

compared with changes of water supply to evaluate how the water balance may evolve over time.






Prerequisites: Some experience with GIS, spatial modelling, remote sensing

and programming (e.g. R/python/matlab) would be preferable.




Mapping intertidal topography and assessing mangrove colonization patterns in Suriname from UAV imagery

Supervision: W. Nijland and J. de Vries


Description:

Within the NWO-Wotro project ‘Mangroves and Mud: Monitoring and Modelling Coastal

Dynamics in Suriname’ we study the complex and dynamic coastal ecosystems of Suriname. This coastal region is low-lying, flat and vulnerable for anticipated sea level rise. The area is also essential for agriculture, fresh drinking water and human settlements. The coastal system is extremely complex: large mud supplies from the Amazon river results in mud banks migrating along the coast influenced by complex wind and wave dynamics.

The intertidal areas play a key role in this ecologically rich ecosystem. Our project aims at 1) Process and analyse UAV images captured in July 2019, February 2020 and

potentially September 2020. 2) Find relevant surface characteristics from the images that link (potential) mangrove

colonization patterns to changes in topography

3) Quantifying mangrove establishment on intertidal flats The proposed topic is a desk study for a student with a background in remote sensing, ecology and a keen interest in image processing. The topic can be adjusted to fit the student’s interest. Possible research questions are: *) What is the quality of UAV generated image products and how do outputs compare to other remote sensing products such as Sentinel and PlanetScope *) what relevant

surface characteristics (elevation, mud cracking) can be found and quantified over the period of interest. *) What characteristics of planted mangroves and consequential survival rates can be found from the UAV images.

Followed courses like GEO4-4406 Land Surface Process Modelling, GEO4-2303 Ecosystem Modelling, image processing experience (Agisoft/MetaShape) or programming experiences in R/Python/Matlab are a pre.

Further reading;

Proisy, C., Gratiot, N., Anthony, E. J., Gardel, A., Fromard, F., & Heuret, P. (2009). Mud bank colonization by opportunistic mangroves: a case study from French Guiana using lidar data. Continental Shelf Research, 29(3), 632-641.

Location: Utrecht

Period: Spring / summer 2020 – winter 2020


Track: Geohazards and Earth Observations

Prerequisites: GEO4-4408 Remote Sensing

Contact / info: [email protected] [email protected]







Vegetation development and Carbon sequestration in the Jordan Badia

Supervision: Geert Sterk

In cooperation with: Stefan Strohmeier / Mira Haddad (ICARDA, Jordan)

Description:

The Department of Physical Geography collaborates with the International Centre for Agricultural Research in the Dry Areas (ICARDA). ICARDA is a large research institute with scientists from over 25 countries and excellent facilities. The main work done by ICARDA is crop breeding to develop improved crop varieties for the WANA region (West Asia and North Africa). For more information about ICARDA, see their website

http://www.icarda.cgiar.org/. In addition to crop breeding, ICARDA also works on natural resources conservation, with an emphasis on water management and soil degradation research. For one of their current projects at the Amman office in Jordan, ICARDA is searching for an MSc student to conduct the following research:

Effectiveness of water harvesting in improving vegetation cover and C-sequestration.

The Badia or desert of Jordan covers nearly 80% of the country and is home to the Bedouin people. Lack of rainfall is the main feature of the Badia, and reduces its economic importance. The area is mostly used for sheep grazing and some limited crop growth in more wet areas. Vegetation cover is inherently scarce, and it has been claimed that desertification due to overgrazing is an increasingly big problem. The annual rainfall is low (<150 mm) and usually comes in sporadic but intense storms. Water harvesting (WH) techniques are implemented in the Badia to improve water

storage, reduce soil erosion, increase vegetation cover, and store Carbon. The estimation of the effectiveness of WH in increasing vegetation cover and C-sequestration is important to determine ecosystem services of WH and justify their use at large scale. Detailed research will be conducted at a site with WH structures. Data about vegetation productivity and C-sequestration will be collected and used to estimate the improvement of vegetation productivity and C-sequestration for larger areas of the

Badia where WH could be implemented.

The aim of the project is to quantify water productivity and vegetation cover changes in relation to WH structures in the Badia of Jordan. The work will comprise a literature study on C-sequestration in arid environments, field data collection (soil properties, vegetation cover, Carbon storage), data analysis, and C-sequestration quantification.

A three months stay at ICARDA in Jordan will be part of this thesis research.

Location: Utrecht and Jordan (Amman)

Period: Sept. 2020 – Feb. 2021 or later



Fits in track 2:

Prerequisites:


http://www.icarda.cgiar.org/






Quantification of wind erosion and dust production in the Jordan Badia

Supervision: Geert Sterk

In cooperation with: Stefan Strohmeier / Mira Haddad (ICARDA, Jordan)

Description:

The Department of Physical Geography collaborates with the International Centre for Agricultural Research in the Dry Areas (ICARDA). ICARDA is a large research institute with scientists from over 25 countries and excellent facilities. The main work done by ICARDA is crop breeding to develop improved crop varieties for the WANA region (West Asia and North Africa). For more information about ICARDA, see their website

http://www.icarda.cgiar.org/. In addition to crop breeding, ICARDA also works on natural resources conservation, with an emphasis on water management and soil degradation research. For one of their current projects at the Amman office in Jordan, ICARDA is searching for an MSc student to conduct the following research:

Quantification of wind erosion and dust production in the Jordan Badia.

The Badia or desert of Jordan covers nearly 80% of the country and is home to the Bedouin people. Lack of rainfall is the main feature of the Badia, and reduces its economic importance. The area is mostly used for sheep grazing and some limited crop growth in more wet areas. Vegetation cover is inherently scarce, and it has been claimed that desertification due to overgrazing is an increasingly big problem. The annual rainfall is low (<150 mm) and usually comes in sporadic but intense storms.

Wind erosion is one of recurrent land degradation problems in the Jordan Badia. Massive dust storms can form due to drought, strong winds and lack of protective vegetation cover. Currently, ICARDA is experimenting with water harvesting (WH) techniques to stimulate vegetation growth in the Badia. In the already implemented WH structures vegetation growth has been spectacular, and it is believed that the vegetation cover will reduce the wind erosion risk. The estimation of the effectiveness of WH in decreasing

wind erosion amounts is important to determine ecosystem services of WH and justify

their use at large scale. Detailed research will be conducted at a site with WH structures. Data about vegetation growth, canopy characteristics and wind speed reduction will be collected and used to model wind erosion amounts with and without WH structures implemented. The aim of the project is to quantify wind erosion and dust production with and without

WH structures in the Badia of Jordan. The work will comprise a literature study on wind erosion in the Badia, field data collection (soil properties, vegetation cover, wind speed), data analysis, and wind erosion modelling. A three months stay at ICARDA in Jordan will be part of this thesis research.

Location: Utrecht and Jordan (Amman)

Period: Sept. 2020 – Feb. 2021 or later



Fits in track 2: -

Prerequisites: Land Degradation, Meteorology








Vegetation resilience and species composition changes in north Tanzania

Supervision: Geert Sterk, Maarten Zeylmans

In cooperation with: Tanzania Agricultural Research Institute

Description:

The Maasai are a Nilotic ethnic group of semi-nomadic people inhabiting southern Kenya and northern Tanzania. Their traditional way of life is to move around with free-roaming cattle herds, but they also have settlements where they return from time to time, or part of the family is staying permanently. The traditional landscape where the Maasai herders roam is a savannah landscape with grasses, shrubs and trees. The Maasai share

these environments with many wildlife animals. The Tanzanian and Kenyan governments have instituted programs to encourage the Maasai to abandon their traditional semi-nomadic lifestyle and permanently settle in villages. This allows the governments to get grip on the life of the Maasai, and for instance to guarantee education for children. Settling in villages also means that the distances herders travel

with their livestock reduce and grazing pressure increases.

In a previous MSc thesis research land use/cover changes between 1985 and 2019 have been studied using remote sensing images from Google Earth Engine. The results did not show important changes in land use/cover classes, but the land cover is strongly influenced by drought in the area, which is becoming more frequent due to climate change. Vegetation cover depends on the amounts of rainfall during the bi-annual rainy seasons and can be variable. The remote sensing analysis showed a high resilience of the vegetation, even after multiple drought years. However, the Maasai herders

complain that the more palatable vegetation species are disappearing and are replaced by other, less palatable species. Lack of adequate grazing resources is a serious constraint for Maasai livestock activities. The aim of this thesis research will be to study the changes in vegetation species composition and determine the causes for these changes in a Maasai area in northern

Tanzania. This will be done by using high-resolution satellite imagery (e.g. SENTINEL)

and field research on vegetation cover and species changes. The work will consist of 1) a literature study on vegetation species naturally occurring in the area, 2) in-depth remote sensing analysis of vegetation cover changes, 3) vegetation surveys in different areas, and 4) interviews with Maasai nomads in north Tanzania. A three-months period of field work in north Tanzania, in collaboration with the District Agricultural Office and the Tanzania Agricultural Research Institute (TARI) will be part of this thesis.

Location: Utrecht and Tanzania (Mto Wa Mbu)




Fits in track 2: -

Prerequisites: Remote Sensing






Geomorphology and gully erosion in the Lake Manyara basin in northern Tanzania

Supervision: Geert Sterk, Wim Hoek


Description:

The Rift Valley in north Tanzania is characterized by a semi-arid climate. The natural vegetation is dominated by savanna with scattered trees, shrubs and grasses. Traditionally the area is occupied by the Maasai, a Nilotic ethnic group of semi-nomadic people. Their traditional way of life is to move around with free-roaming cattle herds.

The Maasai share the savanna with many wildlife animals. Lake Manyara is an important wetland located in the Rift Valley, and is a national park with abundant wildlife resources. The lake has reduced in size over the last decades, but the reasons for this shrinkage are not well known. The different causes could be

drought, water diversions for irrigation and enhanced sedimentation due to land degradation in the catchment area. One of the possible reasons for enhanced

sedimentation could be gully erosion in the catchment area. Gully formation seems to be mostly occurring in soft, volcanic materials that are present in the area. The aim of this study is to determine the relation between geomorphological units and the development and growth of gullies around lake Manyara. The work will consist of 1) a literature review on gully formation and rates in relation to soil material, 2) a remote sensing analysis of the locations of gullies in the area, 3) geomorphological mapping of

the area, and 4) assessing the amounts of sediment generated by individual gullies. A three-months period of field work in north Tanzania, in collaboration with the District Agricultural Office and the Tanzania Agricultural Research Institute (TARI) will be part of the thesis.






Prerequisites: Remote Sensing, Geomorphology






Soil resources and water erosion risk in the Lake Manyara basin in northern Tanzania

Supervision: Geert Sterk, Rens van Beek


Description:

The Rift Valley in north Tanzania is characterized by a semi-arid climate. The natural vegetation is dominated by savanna with scattered trees, shrubs and grasses. Traditionally the area is occupied by the Maasai, a Nilotic ethnic group of semi-nomadic people. Their traditional way of life is to move around with free-roaming cattle herds.

The Maasai share the savanna with many wildlife animals. Lake Manyara is an important wetland located in the Rift Valley, and is a national park with abundant wildlife resources. The lake has reduced in size over the last decades, but the reasons for this shrinkage are not well known. The different causes could be

drought, water diversions for irrigation and enhanced sedimentation due to land degradation in the catchment area. One of the possible reasons for enhanced

sedimentation could be water erosion on agricultural land, which has spread in the catchment area due to population increase. The risk of water erosion is largely determined by the climate, topography, land use and soil characteristics. So far, there is not much information available on soil types and characteristics, which makes quantification of water erosion difficult. The aim of this study is to determine the water erosion risk and quantities on soils

around lake Manyara. The work will consist of 1) a literature review on water erosion in the study area, 2) a remote sensing analysis of land use and cover using high-resolution imagery, 3) soil mapping and soil characterization of the area, and 4) modelling water erosion in the study area and related sediment transport to lake Manyara. A three-months period of field work in north Tanzania, in collaboration with the District Agricultural Office and the Tanzania Agricultural Research Institute (TARI) will be part of

the thesis.






Prerequisites: Land degradation, Modelling






Integrated modelling of fluvial futures

Supervision: Menno Straatsma, Hans Middelkoop, Elisabeth Addink

In cooperation with: Dekker BV – to be determined

Description:

The river system consists of three interacting components, which can be characterized as the hydrosystem, the ecosystem, and the socio-economic system. In time, the autonomous development of the river system is combined with additional pressures from climate change and socio-economic developments, which necessitate terraforming interventions in lowland fluvial areas. We seek MSc students that wish to focus on any

of the following aspects:

• Cyclic floodplain rejuvenation and effects on biodiversity and hydrodynamics tools:

GIS, RiverScape-Routines, hydrodynamic modeling

• BIOSAFE biodiversity modeling of intervention effectiveness

• Cost-benefit trade-offs in flood mitigation measures

tools: Literature review on cost, hydrodynamic modeling, optimization

• Mapping ecosystem services over time and space.

tools: multi-temporal and/or object-based image analysis; GIS

See https://github.com/UU-Hydro/RiverScape for examples and code






Prerequisites: Depending on the topic: Land surface process modelling, Remote sensing, River and delta systems




The rise and fall of riparian vegetation patches

Supervision: Elisabeth Addink, Menno Straatsma

In cooperation with: ---

Description:

Floodplains form a dynamic environment for vegetation, with interactions between the river and vegetation. Climax vegetation comprises riparian forest patches, which survive relatively short due to hydrodynamic disturbance. In its turn, the presence of vegetation influences the hydrodynamics of the water and thus e.g. flood risk. Vegetation is included in morphodynamic models, often as a static parameter, sometimes as a

variable affected by processes steering seedling, growth, survival or death. These models produce patterns that look similar to what we observe in nature, but true validation data are lacking. In this topic you will work with a set of 11 land cover maps of a stretch of the river Allier in France, spanning over 50 years (1946 to 2002). The river Allier is a freely

meandering river with little human restrictions, which shows in the strong dynamics of the meanders. The set was built by object-based classification of aerial photographs and

contains information on high and low vegetation and the size of the patches. The question we like to answer is how the large patches of high vegetation evolve. Is it a small patch growing bigger, or do two small patches merge into a larger one? What happens with large patches: do they merge? And when ithey disappear, does they fall apart into smaller patches, does it deteriorate at the edges or is it eroded by the river? Do locations recently left by the river favour high vegetation patches or offer the

edges of the floodplain a safer spot? You will implement a spatio-temporal network, which links the patches over time and thus reveal the answers to the main questions. Probably, not every large patch follows the same trajectory and likely there are some categories of trajectories describing the rise and fall of the patches. The value of the project is three-fold: it will provide validation data for hydrodynamic

models that include vegetation development, it will show different categories of

trajectories which will help when building models and the developed method might be applied in other dynamic habitats to characterize vegetation development.






Prerequisites: Experience with GIS and scripting, preferably in Python.

Enthusiasm for scripting/computer work.




Quantification of vegetation-erosion feedbacks on steep lateral moraine slopes in Turtmann Valley, Switzerland

Supervision: Dr. Jana Eichel, Dr. Tjalling de Haas

In cooperation with: Dr. Daniel Draebing (University of Bayreuth, Germany), Dr. Teja Kattenborn (Karlsruhe Institute of Technology, Germany), Dr. Alastair Curry (University of Hertfordshire, UK)

Description:

As glaciers retreat, steep lateral moraines built up during the Little Ice Age are eroded by mass movement and soil erosion processes. At the same time, vegetation colonizes

their slopes and potentially stabilizes them. This vegetation stabilization of lateral moraine slopes, especially in the context of ecosystem engineering, has rarely been quantified. Yet, understanding is needed to evaluate current and future landscape and ecosystem change in glacier forelands and improve their sediment and natural hazard management.

The goal of the project is to quantify vegetation-erosion feedbacks on lateral moraine

slopes with a focus on slope stabilization by ecosystem engineering. The student will work on two established erosion plots (25 x 25 m) in the Turtmann glacier foreland (Switzerland). Prior to fieldwork, existing DEMs and orthophotos (2018, 2019) will be analysed and DEMs of Difference and vegetation maps created to assess erosion and vegetation patterns. During fieldwork, UAV flights will be carried out and results from first analyses checked in the field. Field data will subsequently be analysed. Erosion rates and patterns will be compared to vegetation distribution and composition and

interpreted in relation to existing geomorphic, ecologic and soil mechanical data. Thereby, vegetation effects on moraine slope stability and erosion will be identified. This project builds on biogeomorphic research of the supervisor J. Eichel carried out in Turtmann glacier foreland with international collaborators since 2011. Therefore, the results will likely be used in peer-reviewed journal article(s), on which the student will

be one of the authors.

Location: Data analysis at Utrecht University Field measurements at Turtmann glacier foreland (Switzerland)

Period: Fieldwork July/August, analysis prior and subsequently




Prerequisites: -




Remote sensing of a tidal flat, scaling from UAV mosaics to satellite time-series

Supervision: Dr EA Addink, Dr W Nijland


Description:

The Wadden Sea is recognized as an important European ecological area (Natura2000) and as a Unesco World Heritage site. Its tidal flats provide forage and habitat to many birds, fish, and other species. The Vlakte van Kerken is a tidal flat near Texel where we sampled sediment, chlorophyll and macrozoobenthos (worms, snails, molluscs, etc), concurrent with collecting UAV images on a monthly basis. The UAV image mosaics

contain Red, Green, Blue, and NIR bands and have a 5cm pixel size. Besides the eight UAV mosaics collected in 2019, satellite images from Planet (3m pixels) and Sentinel-2 (10m pixels) are available for the area. Through object-based image analysis and machine learning we are able to predict

sediment characteristics and chlorophyll concentrations at the surface which are important drivers of the tidal flat ecosystem. Analysis of field samples combined with

the UAV images provided a distinct set of relevant image variables which mostly represent image texture. We assume that these texture variables do change between images at different resolutions which impacts both prediction accuracy and optimal variable selection. In this project you will aim to find out which images produce the most accurate maps for sediment, chlorophyll, and biodiversity variables, and to understand the effect of

differences in image resolution. Possible research questions are 1: How does image texture and information content differ between UAV, Planet. and Sentinel images? 2: Which variables from each type of images are the best predictors for the field properties and why? 3: How accurate can we predict sediment, chlorophyll, and biodiversity for the study area using the available data?

This topic is suited for an MSc student with a background in remote sensing, data

analysis, and interest in tidal ecosystems. The work will be a desk study involving a significant amount of image processing and the building of predictive models using available datasets, but there are opportunities to join one or two field campaigns which will be planned to gather more field samples and collect additional UAV datasets in collaboration with NIOZ Texel and other student projects.






Prerequisites: Remote Sensing, and an interest to work with scripts (R or Python)




Looking from the air below the surface of the Wadden Sea: using objects to

map benthic macrofauna in UAV images

Supervision: EA Addink and W Nijland

In cooperation with: K. Philippart, UU / NIOZ, Texel

Description:

The Wadden Sea is recognized as an important European ecological area (Natura2000) and as a Unesco World Heritage site. The shallow sea with large tidal flats provides forage and habitat to many birds, fish, and other species. Benthic macrofauna are a key part the ecosystem as they process organic matter, recycle nutrients and are an important food source. They live partly at, but mostly below the surface. Individual species have specific environmental requirements, together shaping their ecological

niche. Groups of species might share part of their niches. The recognized value of the Wadden Sea requires that monitoring of the status and development of the system is

frequent and concise. As part of an annual monitoring program point samples of the benthic macrofauna, sediment, and chlorophyll are collected on a 500m grid by NIOZ, the Royal Netherlands Institute of Sea Research. We will set up a similar scheme much denser sampling on a mudflat next to the Wadden shore of Texel and combine this with Unmanned Aerial

Vehicle (UAV or drone) flights. Flights are repeated seasonally to create a temporal dataset of images and sample data. Two students will be working on these data, one from Earth, Surface and Water and one from Marine Sciences. The topic proposed here focuses on the ESW part, to analyse the images using object-based image analysis. The challenge is to find surface characteristics that predict benthic species diversity as the animals themselves live

mostly below the surface and cannot be directly detected. A pilot study revealed that texture characteristics in the image have a strong predictive power, while spectral information is of less importance. Possible research questions in this Master topic are: *What image characteristics best represent benthic-macrofauna distribution. *Can we define and locate biodiversity hot

spots? *Do biodiversity hot spots change position, and what are the spatial and

temporal dynamics of their locations? And more technical: *What is the optimal scale to predict the hot spots or the abundance of individual species? *Can individual species abundance be predicted using the shared ecological niche of a larger group of species? The fieldwork will be done jointly: You will help collecting the benthos samples and the other student will help you when flying the UAV. You will process the data and stitch the photos into a mosaic, while the other student will work on identification of the benthos.

Location: Utrecht with fieldwork at Texel

Period: Spring/Summer 2019 – Winter 2020

Number of students: 1 or 2 (working on different periods or different questions)

Track: GHEO

Prerequisites: Remote Sensing, Data analysis, and an interest in ecology

Contact / info: [email protected] [email protected]



graduation research projects 2020

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