CALL QUANTIFICATION AND PREDICTION OF EROSION PROCESSES IN GERMANY RESEARCH ASSIGNMENT NUMBER STAFUE-21-12-KLEI AS PER 05/07/2021

Call
Quantification and Prediction of Erosion Processes in
Germany

Research assignment number STAFuE-21-12-Klei

As per 05/07/2021

        Geschäftszeichen: SG01203/27/1-2021#1 – Objekt-ID: 885989 – Revision: 00

Quantification and Prediction of Erosion Rates and Processes in Regions with
Dynamic Landscape and River Network Development

1         Cause and subject
On September 21, 2016, the Bundesgesellschaft für Endlagerung mbH (BGE) was
founded in the business division of the Federal Ministry for the Environment, Nature Con-
servation and Nuclear Safety based on the act on the reorganization of the organizational
structure in the area of final disposal from June 2016.
As of April 24, 2017, the task of the Federal Government was transferred to the BGE in
accordance with Section 9a (3) Sentence 1 of the (AtG). Pursuant to Section 3 of the Act
on the Search and Selection of a Site for a Repository for High-Level Radioactive Waste
(Site Selection Act of May 5, 2017 (BGBl. I p. 1074)), last amended by Article 247 of the
Ordinance of June 19, 2020 ((BGBl. I p. 1328) (StandAG)), the BGE is the project spon­
sor for the site selection procedure.
On September 5, 2017, the start of the site selection process took place in Berlin. At the
beginning, a "white map" of Germany was assumed. The BGE started with the exclusion
of regions according to the legally defined exclusion criteria, minimum requirements and
by implementation of the geoscientific consideration criteria. On September 28, 2020,
the first step of Phase I was completed with the publication of the “Sub-areas Interim
Report”. At this time, 90 areas with an area of approx. 240,874 km² have been desig­
nated as sub-areas according to Section 13 StandAG.
In Step 2 of Phase I, the BGE implements the comparative analysis based on existing
data, in accordance with the legally defined geoscientific and planning-scientific consid­
eration criteria, as well as the representative preliminary safety investigations. The BGE
then proposes siting regions for surface exploration to the Federal Office for the Safety
of Nuclear Waste Disposal (BASE). Phase I has been completed with the decision of the
German Bundestag and the Bundesrat on which siting regions will undergo surface ex­
ploration.
When assessing the safe confinement of radionuclides in a repository system for high-
level radioactive waste, it must be ensured that the effective containment zone retains
its barrier function over the period of one million years. Processes that can reduce or
decrease the barrier properties (e.g. rock permeability, thickness, extension of the effec­
tive containment zone) include erosion processes, which can cause erosion of the over­
burden, decompaction of host rock and, in extreme cases, direct surface exposure of the
effective containment zone.
Interactions and feedback mechanisms of endogenous processes, e.g. large-scale sur­
face uplift, exogenous processes, such as climatic changes and the resistance of the
local lithology to erosion drive the intensity of erosion processes. Furthermore, changes
in the equilibrium state of the drainage system due to drainage capture events and river
reversal can lead to a sharp increase in fluviatile deepening. Such river network reorgan­
izations can also occur in relatively short periods of time (less than one million years)
and result in a sharp increase of linear erosion and denudation (large-scale erosion) due
to a lower erosion base (Yanites et al. 2013).

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Quantification and Prediction of Erosion Rates and Processes in Regions with
Dynamic Landscape and River Network Development

So far, information on erosion and landscape evolution processes in Germany is limited
to regional studies (e.g. Schaller et al. (2001); Strasser et al. (2010); Winterberg & Willett
(2019); Meyer et al. (2010). This research call consists of two work packages. Work
package 1 (Chapter 2.1), aims on discussing and evaluating the relevant erosion pro­
cesses in a nationwide analysis by compiling all information on erosional processes and
events that acted since the early Miocene in form of a report including informative maps.
On this basis, the next step is to derive the possible erosion amounts for the next one
million years using a methodology, which is applicable Germany-wide. The results of this
work package should allow defining the depth of the containment area relative to the
terrain surface in a site-specific scale. Furthermore, the results serve as a basis for esti­
mating the extent of possible decompaction and the resulting effects on the safety of a
potential repository. Processes related to glacial tunnel valleys should not be addressed,
since these deep-reaching erosion processes are already part of a separate BGE re­
search project.
The focus of the second work package (Chapter 2.2) is on a detailed analysis of the
dynamic landscape development processes of the SW-German scarpland. As a result of
extensive river network reorganizations, Northern Switzerland and Southwest Germany
have been characterized by a dynamic landscape evolution since the late Miocene (Vil­
linger (1998); Villinger (2003); Ziegler & Fraefel (2009)). About 4.2 million years ago, a
major reorganization in the drainage system between Rhenish and Danubian tributaries,
due to river capturing of the Aare by the Rhine caused the incision of Aare by up to 800
meters (Yanites et al. 2013). This progressive expansion of the Rhenish river catchment
area at the expense of the Danube catchment, also takes place through the expansion
of the Neckar catchment. As in Northern Switzerland, there is also evidence for increased
river incision rates by directed erosion in the SW-German scarpland. Moreover, these
processes are superimposed by the episodic increase of erosion rates during quaternary
cold stages (Strasser et al. 2010).
The incision of the river systems is accompanied by large-scale denudation, which re­
sulted in the southwestward retreat of escarpments. The latter, are build by Jurassic and
Triassic erosion-resistant lithologies, which are important for the protection of the effec­
tive containment zone. Work package 2 of this research call therefore concentrates on
quantifying the erosion rates and amounts of the rivers within the SW-German scarpland.
Taking into account the expected climatic evolution as well as the erosion resistance of
the occurring lithologies, the development of the river network system (catchment area
Danube vs. catchment area Rhine) and the resulting maximum expected river incision
depths are to be derived with a suitable method. Furthermore, the question should be
addressed at what rate the retreat of the escarpments, in particular of the Upper Jurassic
carbonates, take place. To derive the expected retreat distance of the escarpments,
within the next one Million years is an important constraint, as the escarpment retreat
may result in the direct surface exposure of the Opalinus clay formation, which is a po­
tential host rock unit.

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Quantification and Prediction of Erosion Rates and Processes in Regions with
Dynamic Landscape and River Network Development

2          Content
With this call, we request project proposals for two work packages by August 25, 2021,
that address the following aspects and questions, with a particular focus on the safety of
a repository for high-level radioactive waste in Germany. The project should start imme­
diately after commissioning and be completed within a period of 2 years.
As both work packages may require different investigation methods and concepts, appli­
cations for individual work packages are also welcome. Processes related to the impact
and formation of tunnel valleys will not be considered in this call for proposals as they
were already covered.

2.1        Work Package 1 – Erosion in Germany
For this work package, we request project proposals that are dedicated to the following
aspects and questions with a special focus on erosion processes at the scale of Ger­
many:
      1) The regional erosion history since the early Miocene is to be compiled on the
         basis of a Germany-wide evaluation of the available information and the results
         are to be produced in the form of a report with corresponding maps.
      2) Subsequently, a suitable methodological approach is to be used to determine the
         local erosion with the aim of forecasting the possible or expected amounts of
         erosion within the next one million years. In this context, a discussion on the re­
         lated uncertainties, which accounts for different endogenous, exogenous and cli­
         matic scenarios, is needed. The results should enable the BGE to determine the
         site-specific depth of the containment area relative to the terrain surface in a site-
         specific scale.

2.2        Working Package 2 – Quantifying Erosion Rates and Processes in Re­
           gions with dynamic Landscape Evolution Processes
With this work package, we request proposals that address the following aspects with a
special focus on the dynamic landscape development in Southwest Germany:
      1) Basis for this work package is a detailed reconstruction and analysis of the land­
         scape and erosion history since the late Miocene.
      2) In combination with suitable methods, the current and future incision rates, as
         well as the expected maximum displacement of the escarpments towards the
         southwest are to be determined. Based on these results, areas within the deter­
         mined subareas should be identified that may possibly be exposed by the erosion
         of the overburden within the next one million years.
In more detail, the proposals should address the following questions:

      •   What incision rates occur in rivers that were formerly a tributary of the Danubian
          catchments and now drain into the Rhenish system?

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Quantification and Prediction of Erosion Rates and Processes in Regions with
Dynamic Landscape and River Network Development

    •   What are the rates of knickpoint migration?

    •   How can findings of the recent and ongoing erosion processes be transferred to
        a model-based forecast of future landscape evolution, taking into account various
        boundary conditions (e.g. climate variability, changes of the erosion base level),
        for the period of the coming one million years?

    •   At what rates have the Triassic and Jurassic escarpments migrated since the
        Miocene? Based on this information - is it possible to derive the position of the
        escarpments in one million years?

    •   With what uncertainties, considering the influence of climate on erosion pro­
        cesses, are the data on the prediction of the questions afflicted?
Note: The focus of the second work package on the southwestern German stratigraphic
landscape is based on the increased landscape development processes occurring there
and the associated high relevance of these processes in these regions.

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Quantification and Prediction of Erosion Rates and Processes in Regions with
Dynamic Landscape and River Network Development

3         References
AtG: Atomgesetz in der Fassung der Bekanntmachung vom 15. Juli 1985 (BGBl. I S.
       1565), das zuletzt durch Artikel 239 der Verordnung vom 19. Juni 2020 (BGBl. I
       S. 1328) geändert worden ist
Meyer, H., Hetzel, R. & Strauss, H. (2010): Erosion rates on different timescales derived
       from cosmogenic 10Be and river loads: Implications for landscape evolution in
       the Rhenish Massif, Germany. International Journal of Earth Sciences, Bd. 99,
       S. 395-412. DOI: 10.1007/s00531-008-0388-y
Schaller, M., von Blanckenburg, F., Hovius, N. & Kubik, P. W. (2001): Large-scale
       erosion rates from In situ-produced cosmogenic nuclides in European river
       sediments. Earth and Planetary Science Letters, Bd. 188, S. 441-458. DOI:
       10.1016/S0012-821X(01)00320-X
StandAG: Standortauswahlgesetz vom 5. Mai 2017 (BGBl. I S. 1074), das zuletzt durch
      Artikel 1 des Gesetzes vom 7. Dezember 2020 (BGBl. I S. 2760) geändert
      worden ist
Strasser, A., Strasser, M. & Seyfried, H. (2010): Quantifying erosion over timescales of
       one million years: A photogrammetric approach on the amount of Rhenish
       erosion in southwestern Germany. Geomorphology, Bd. 122, S. 244-253. DOI:
       10.1016/j.geomorph.2009.06.027
Villinger, E. (1998): Zur Flußgeschichte von Rhein und Donau in Südwestdeutschland.
        Jahresberichte und Mitteilungen des oberrheinischen geologischen Vereins, Bd.
        80, S. 361-398. DOI: 10.1127/jmogv/80/1998/361
Villinger, E. (2003): Zur Paläogeographie von Alpenrhein und oberer Donau. Zeitschrift
        der Deutschen Geologischen Gesellschaft, Bd. 154, S. 193-253. DOI:
        10.1127/zdgg/154/2003/193
Winterberg, S. & Willett, S. D. (2019): Greater Alpine river network evolution,
       interpretations based on novel drainage analysis. Swiss Journal of Geosciences,
       Bd. 112, S. 3-22. ISSN 16618734. DOI: 10.1007/s00015-018-0332-5
Yanites, B. J., Ehlers, T. A., Becker, J. K., Schnellmann, M. & Heuberger, S. (2013): High
       magnitude and rapid incision from river capture: Rhine River, Switzerland.
       Journal of Geophysical Research: Earth Surface, Bd. 118, S. 1060-1084. ISSN
       2169-9003. DOI: https://doi.org/10.1002/jgrf.20056
Ziegler, P. A. & Fraefel, M. (2009): Response of drainage systems to Neogene evolution
        of the Jura fold-thrust belt and Upper Rhine Graben. Swiss Journal of
        Geosciences, Bd. 102, S. 57-75. ISSN 16618734. DOI: 10.1007/s00015-009-
        1306-4

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