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Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp, Final Conference, Bozen, 9. 06. 2015

Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

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Page 1: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Sediment cascades and sediment budgets in Alpine basins

Lothar Schrott

Department of Geography, University of Bonn

SedAlp, Final Conference, Bozen, 9. 06. 2015

Page 2: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Content

Sediment cascade and sediment budget – general considerations and concepts

Temporal and spatial scales

Methods (mapping, geophysics, modelling/GIS)

Case studies: Gradental (Hohe Tauern, Austria)

Turtman-valley (Wallis, Switzerland)

Schnalstal (South Tyrol)

Pasterze (Hohe Tauern, Austria)

Lessons learned: Conclusion & Outlook

2 2

Page 3: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Caine (1974)

Sediment cascade

Davies & Korup (2010): 90

3 3

Page 4: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

4

(mo

difie

d fro

m C

ho

rle

y &

Ke

nn

edy 1

97

1)

Characteristics

► flow of energy and mass

► input – storage – output

► coupling – decoupling

► regulators (e.g. slope, vegetation)

► buffering capacity

Sediment cascade spatial scale

Reintal, 2012

4

Page 5: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Sediment budget

5

I ± ΔS = O

Slaymaker (2003), 72 “The sediment budget is defined as the accounting of sources, sinks and redistribution pathways of sediments in a unit region over unit time”.

(Slaymaker 2003, 71)

“A sediment budget is an accounting of the sources and disposition of sediment as it travels from its point of origin to its eventual exit from a drainage basin.“ (Reid & Dunne, 1996)

Storage

ΔS = I - O

5 Hinderer (2012)

Page 6: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Approaches in sediment budget studies, sediment fluxes and storages

6

Hinderer (2012)

Sediment

budgets

6

Page 7: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

I – O = ΔS

Sediment storage

Denudation

Process

coupling

Sedimentation

Landform evolution

Input

Output

DRme = SV ρb/ (ρr Ad T) [mm a-1]

SY = SV ρb/(AdT) [t km-2 a-1] Sediment yield ≠ sediment budget

7 7

Page 8: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

What do we need to construct a sediment budget?

1. Recognition and quantification of transport processes

2. Recognition and quantification of storage elements

3. Identification of linkages amongst transport processes

From sediment yield to sediment budget

Sediment yield [t/a]

specific sediment yield [t/km²/a]

sediment delivery ratio, [SDR = Y/E]

sediment budget [I=O±∆S]

8 8

Page 9: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Process-oriented

studies

Coupling of

geoarchives with

sediment budget

models

Stratigraphical approaches

(geoarchives)

Time scale

Spatial scale

Re

gio

na

l a

pp

roa

ch

es

“The biggest challenge in use of sediment budgets is in making the link between intensively studied smaller scale systems to the global scale“

(Slaymaker 2009, 19)

(Dikau, Hoffmann, Houben, Schrott 2006)

9 9

Page 10: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Tony Parsons Professor of Sediment Systems, Department of Geography, University of Sheffield

10

Page 11: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Sediment cascades provide answers to

+ sedimentary systems

+ quantitative approach of sediment flux and storage

but…

- lacks a consideration of time

- some quantities remains unmeasured

11

+ flowpath (direction) of sediments + amount and type of temporary sinks, processes and regulators + subsystems + coupled and decoupled areas but… - not considering process response systems

Sediment budgets provide answers to

11

Page 12: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Specific sediment yields in the Alps (data from river loads and reservoirs)

12

Hinderer et al. 2013

negative trend with basin area

poor corr. with relief positive trend with

discharge positive trend with glaciated areas

12

Page 13: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Large scale versus small scale studies >> the missing link Large scale studies: • Jäckli (1957) • Hinderer (2001) • Hinderer (2012, 2013) • Straumann & Korup (2009)

Small-scale sediment budget studies (tributaries): • Rapp (1960) • Schrott et al. (2003) • Götz et al. (2013)(this talk) • Otto et al. (2009)(this talk)

13

Large scale studies focussing on valley & lake fills

Small scale studies focussing on sediment input, storage and output

13

Page 14: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Why are tributaries important?

• The are an important component in the sediment cascade

• The are an important component in the sediment budget (e.g. Illgraben supplies 5-15% of the entire sediment volume of Rhone River to Lake Geneva)

• They are subject to intense changes and probably the most dynamic area in recent times (glacier retreat, increasing proglacial area, permafrost degradation, etc.)

• Our knowledge of temporary storages, sediment input and output is poor

14 14

Page 15: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Methods Geomorphological

Mapping

Terrestrial Laserscanning/TLS

2D Electrical Resistivity Tomography/ERT

Refraction Seismic /RS

Ground-Penetrating Radar/GPR

Core-Drilling, Sampling, Radiocarbon Dating [AMS; a cal. B.P.]

Palynologic Analyses (cooperation R. Krisai, Univ. Salzburg)

GIS-based Bedrock Interpolation (spline) and 3D Modelling of Landform Volumes

(cut/fill)

bedrock

15 su

rface

sub

surface

lab

Page 16: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Case study (local scale)

Gradental (Hohe Tauern, Austrian Alps)

16 16

Page 17: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

The Gradenmoos Basin

rockwall retreat can be reconstructed in detail, since (1) sediment output can be neglected,

I = S

- a (semi)closed

denudation- accumulation-system

- subcatchment: 4.5 km², 1920 - 3283 m)

- negligible suspended and no clastic output

- multiple processes (debris flow, rockfall, fluvial, lacustrine)

17 17

Götz et al. (2013)

Page 18: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

The Gradenmoos Basin

rockwall retreat can be reconstructed in detail, since (1) sediment output can be neglected, (2) source areas (3D) are clearly defined,

I = S

- a (semi)closed

denudation- accumulation-system

- subcatchment: 4.5 km², 1920 - 3283 m)

- negligible suspended and no clastic output

- multiple processes (debris flow, rockfall, fluvial, lacustrine)

- favourable logistics and accessibility

18 18

Götz et al. (2013)

Page 19: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

The Gradenmoos Basin

rockwall retreat can be reconstructed in detail, since (1) sediment output can be neglected, (2) source areas (3D) are clearly defined, (3) sediment storage volumes can be quantified (spatial scale, method. approach),

I = S

- a (semi)closed

Denudation Accumulation System

- subcatchment: 4.5 km², 1920 - 3283 m)

- negligible suspended and no clastic output

- multiple processes (debris flow, rockfall, fluvial, lacustrine)

19 19

Götz et al. (2013)

Page 20: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

The Gradenmoos Basin

rockwall retreat can be reconstructed in detail, since (1) sediment output can be neglected, (2) source areas (3D) are clearly defined, (3) sediment storage volumes can be quantified (spatial scale, method. approach), (4) intermediate storage is small (small source-sink distance, steep gradient), and

I = S

- a (semi)closed

denudation- accumulation-system

- subcatchment: 4.5 km², 1920 - 3283 m)

- negligible suspended and no clastic output

- multiple processes (debris flow, rockfall, fluvial, lacustrine)

20 20

Götz et al. (2013)

Page 21: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

The Gradenmoos Basin

rockwall retreat can be reconstructed in detail, since (1) sediment output can be neglected, (2) source areas (3D) are clearly defined, (3) sediment storage volumes can be quantified (spatial scale, method. approach), (4) intermediate storage is small (small source-sink distance, steep gradient), and (5) onset of sedimentation can be established.

I = S

- a (semi)closed

denudation- accumulation-system

- subcatchment: 4.5 km², 1920 - 3283 m)

- negligible suspended and no clastic output

- multiple processes (debris flow, rockfall, fluvial, lacustrine)

21 21

Götz et al. (2013)

Page 22: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Results - Long-term (postglacial) sediment storage volumes

6.3 | 40

0.3 | 19 3.9 | 37 3.7 | 32

0.01 | 4

0.3 | 23 0.4 | 6

0.5 | 6

1.9 | 31

1.2 | 33

0.6 | 7

0.2 | 4

0.8 | 20

Total : 19.7 Mio m³ (postglacial volume: 18.3 Mio m³)

Landform volumes (Mio m³) and sediment thickness (m)

lake level: 1915.7 m

bedrock mesh

fluvial (+lacustrine!) deposits

debris flow (+lacustrine?) deposits

rockfall talus

22 Götz et al. (2013)

Page 23: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Short-term sediment flux 2009-2014

Two recent debris flows (TLS, DEMs of Diff.)

23

Götz & Schrott (2015) submitted

Page 24: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Short term input overbalances the postglacial rate by an order of magnitude !

Götz & Schrott (2015) submitted

Page 25: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Case study

Turtmann valley (Valais, Switzerland)

25 25 Otto et al. (2009)

Page 26: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Sediment storage in the Turtmann valley

26

Ott

o e

t al

. (2

00

9),

17

31

26

Page 27: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Sediment cascade and quantification of sediment storage

27

Otto et al. (2009)

27

real surface ~ 140 km²

Over 60% stored in hanging valleys!

Important temporary sinks

Decoupled from the main system

Page 28: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Case study

Schnalstal, South Tirol & Sella, Dolomites

28 28

Page 29: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Source area – permafrost warming

29

Krainer et al. 2012

Sella, Dolomites / Italy Sella, Grödner Joch

Page 30: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Schnalstal, South Tyrol (debris flow activity 1983 – 2006)

30

H 1: Thawing of permafrost (degradation) is causing an increased debris flow

activity

H 2: The presence of permafrost favours the occurrence of debris flows

30

Page 31: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Debris flow activity and permafrost Increasing debris

flow activity between 1983 and 2006 (46%)

Most starting zones of debris flows are situated above 2850 m (with permafrost occurrence)

Increasing active layer depth lead to higher proportions of loose debris

Sattler et al. 2011 31

Alt

itu

de (

m a

.s.l.)

Amount of debris flows (starting zone)

Area (% of total surface area)

Permafrost probable

Permafrost sensitive

Permafrost unprobable31

1983

1997

2006

Amount of debris

flows

Increase

1983-2006

31

Page 32: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Case study

Pasterze (Hohe Tauern, Austrian Alps)

32 32

Page 33: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Sediment cascade and budget, Pasterze

33

(II)

(III)

(I)

(I)

Subsystem Area [km²] Area [%]

Slope (I) 12 30.2

Glacier (II) 20.8 52.3

Glacier forefield (III) 7 17.5

Catchment 39.8 100 33

Geilhausen et al. 2012

Page 34: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Pasterze – dynamic glacier forefield

34

deglaciation

1953-2009:

- increase (1.3 km² /100%) of sediment storage

- main changes in the proglacial & south-western part of the forefield

- since 1998: significant retreat in the south-eastern part

34 Geilhausen et al. 2012

Page 35: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Scenario: Glacier retreat will lead to~600 new lakes in Switzerland! >> This will alter sediment flux and storage in the proglacial area!

35 (Haeberli et al. 2013, Linsbauer et al. 2012)

New lakes as a consequence of glacier retreat (Research roject NFP 61, Switzerland)

Temperature increase of 4°C until 2199, time steps of 15 years

35

Page 36: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Conclusion & Outlook we have achieved…

• sediment cascades help to identify subsystems and the flowpath of sediment fluxes

• sediment budgets can provide a unifying framework

storage component is important for hazard assessment!

we need to…

• focus on linkages between small and large scale (> 500 km²) studies

• focus on sediment-connectivity (coupled-decoupled systems)

• address limitations/uncertainties in sediment budget studies

(only short or unsufficient measured sediment balance equation components)

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Page 37: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Thank you very much for your attention!

"We must above all shift from a culture of reaction to a culture of prevention.

Prevention is not only more human than cure… it is also much cheaper…" (Kofi Annan 1998)

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Page 38: Sediment cascades and sediment budgets in Alpine basins · Sediment cascades and sediment budgets in Alpine basins Lothar Schrott Department of Geography, University of Bonn SedAlp,

Cited Literature Davies T.R.H. & O. Korup (2010): Sediment Cascades in active landscapes. In: Burt, T., & R. J. Allison [Eds.]: Sediment cascades: An integrated approach. John Wiley &

Sons, p. 90.

Caine, N. (1974): The geomorphic processes of the alpine environment. In: Ives, J.D., Barry, R.G. (Eds.): Arctic and Alpine Environments. Methuen, London, pp. 721–748.

Dikau, R., Houben, P., Hoffmann, T. & L. Schrott (2006): Der Sedimenthaushalt geomorphologischer Systeme seit Beginn des menschlichen Einflusses. In: Deutscher Arbeitskreis für Geomorphologie (Hrsg.): Die Erdoberfläche Lebens- und Gestaltungsraum des Menschen. Z. Geomorph., N.F., Suppl.-Bd. 148: 32-40

GEILHAUSEN, M., OTTO, J.-C. & L. SCHROTT (2012): Spatial distribution of sediment storage types in two glacier landsystems (Pasterze & Obersulzbachkees, Hohe Tauern, Austria). Journal of Maps, Vol. 8, No. 3, 242–259

Götz, J., Otto, J.-C. & L. Schrott (2013): Postglacial sediment storage and rockwall retreat in a semi-closed inner-alpine basin (Gradenmoss, Hohe Tauern, Austria). - Geografia Fisica e Dinamica Quaternaria Vol. 36/1, 63-80.

Haeberli, W., Schaub, Y., Huggel, C. and Boeckli, L. (2013, b): Vanishing glaciers, degrading permafrost, new lakes and increasing probability of extreme floods from impact waves – a need for long- term risk reduction concerning high mountain regions. Geophysical Research Abstract, Vol. 15, EGU2013-3273.

Hinderer, M. (2001): Late Quaternary denudation of the Alps, valley and lake fillings and modern river loads. Geodinamica Acta, 14(4), 231-263.

Hinderer, M. (2012): From gullies to mountain belts: a review of sediment budgets at various scales. Sedimentary Geology, 280, 21-59.

Hinderer, M., Kastowski, M., Kamelger, A., Bartolini, C., & Schlunegger, F. (2013): River loads and modern denudation of the Alps—a review. Earth-Science Reviews, 118, 11-44.

Jäckli, H. (1957):Gegenwartsgeologie des bündnerischen Rheingebietes. Ein Beitrag zur exogenen Dynamik alpiner Gebirgslandschaften. Beiträge zur Geologie der Schweiz -Geotechnische Serie 36, 1-135.

Krainer, K., Mussner, L., Behm, M., & H. Hausmann (2012): Multi-discipliary investigation of an active rock glacier in the Sella Group (Dolomites; Northern Italy). Austrian Journal of Earth Sciences, 105(2), 48-62.

Linsbauer, A., Paul, F., & Haeberli, W. (2012). Modeling glacier thickness distribution and bed topography over entire mountain ranges with GlabTop: Application of a fast and robust approach. Journal of Geophysical Research: Earth Surface (2003–2012), 117(F3).

Otto, J. C., Schrott, L., Jaboyedoff, M., & R. Dikau (2009): Quantifying sediment storage in a high alpine valley (Turtmanntal, Switzerland). Earth Surface Processes and Landforms, 34(13), 1726-1742.

Parsons, A. J. (2011): How useful are catchment sediment budgets? Progress in Physical Geography, 36 (I), 60-71.

Rapp, A. (1960): Recent development of mountain slopes in Kärkevagge and surroundings, Northern Scandinavia. Geografiska Annaler, 65-200.

Sattler, K., Keiler, M., Zischg, A., & Schrott, L. (2011): On the connection between debris flow activity and permafrost degradation: a case study from the Schnalstal, South Tyrolean Alps, Italy. Permafrost and Periglacial Processes, 22(3), 254-265.

Schrott, L., Hufschmidt, G., Hankammer, M., Hoffmann, T. & R. Dikau (2003): Spatial distribution of sediment storage types and quantification of valley fill deposits in an alpine basin, Reintal, Bavarian Alps, Germany. - Geomorphology, Vol. 55, 45-63.

Slaymaker, O. (2003). The sediment budget as conceptual framework and management tool. In The Interactions between Sediments and Water (pp. 71-82). Springer Netherlands.

Slaymaker, O., & Embleton-Hamann, C. (2009). Geomorphology and global environmental change. Cambridge University Press, p. 19.

Straumann, R. K., & Korup, O. (2009): Quantifying postglacial sediment storage at the mountain-belt scale. Geology, 37(12), 1079-1082.

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