Sediment management along rivers in Austria · Sediment management along rivers in Austria I Helmut Habersack ... bank erosion etc. sediment transport, grain ... measurement / modelling

University of Natural Resources and

Life Sciences Vienna

Department of Water, Atmosphere and

Environment

Sediment management along rivers in Austria I Helmut Habersack

Sediment management along rivers in Austria

H. HABERSACKChristian Doppler Laboratory for Advanced Methods in River Monitoring, Modelling and Engineering, University of Natural

Resources and Life Sciences, Vienna




Environment


� Role of sediments in water management

� River Scaling Concept and sediment regime

� Sediment management along rivers in Austria - examples

� Sediment transport monitoring and modelling

� Conclusions

Contents




Environment


Sediments have centralfunctions in rivers

� Development of the river bed and morphodynamics

� Prerequisite for the minimization of negative trends (e.g. river

bed degradation)

� Habitats

� Groundwater flow

� Nutrient transport…

�River engineering, flood protection, hydropower, torrent

control, restoration…




Environment


Surplus

Deficit




Environment


Input Output

Erosion

Tributaries

Input Dredging

Transport

Deposition

Remobil.

River Gauging

station

Mean

discharge

[m³/s]

Analysed

length

[km]

Deficit

[%

Length]

Surplus

[%

Length]

Danube Wien

Reichsb.

1931 350 30 70

Drau Drauhofen 112 214 27 59

Mur Bruck/Mur 105 280 66 24

Enns Steyr 202 186 33 47

Inn Kirchbichl 289 258 44 29

Salzach Golling 142 182 49 13




Environment


Consequence river bed erosion

� Risk of bed changes during floods

� Risk of river bed break through

� Lowering of groundwater table

� No dynamic gravel bars (spawning places …)

� Loss of gravel bed in a few decades

� Reversal of river morphological processes

is slow, thus urgent need for sustainable development




Environment


River bed “break through”

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

distance [m]

m a

. sl.

gravel

fine, marine

sediments

7.10.53

18.03.75

10.10.95

15.10.01

26.11.02

ca. 4mca. 3m

ca. 3m

Degradation 1953 bis 2001: ca. 3 m

Degradation flood August 2002: 3 - 4m, 2 pools

Hengl, 2004




Environment


Width changes in floodsSpecific stream power

R2 = 0.7303

0

1

2

3

4

5

6

7

0 2000 4000 6000 8000

Gemittelte Strömungsenergie[W/m²]

Bre

ite

nä

nd

eru

ng

sve

rhä

ltn

is

na

ch

/vo

r H

och

wa

sse

r[-

]

Bregenzerach

Rosanna

Trisanna

Alfenz

Lech

Krapesch, Hauer, Habersack, 2011, J. Natural Hazards

River morphological space demand




Environment


Measures against bed degradation

Change of

sediment regime

Increase of

bed resistenceReduction of

energy slope

Minimization of

bed shear stress

Artificial

bedload

input

Activation

natural

bedload input

Bed

pavement

Ground

sills Steps

Upstream

input

(continuum

sources -

torrents -

power plants),

no gravel pits

Side erosion

Open

cover

Adding

coarse

material

Granulo-

metric

bed

improve-

ment

WeirsIncrease

of flow

length

River

widening

Reduction

of

discharge

StepsRock

rampsCascade

step pool –

ramps

Improved

inundation




Environment


Catchment102-104 km

>103 km

PARAMETER / PROCESSES

kont./regional Scale

Sectional Scale1-102 km

local Scale

10-2-1 km

Pointscale10-4-10-2 km

DOWN-

SCALING

geology, tectonics,

climate etc.

catchment-size, geology,

valley development, -form,

erosion potential ..

river morphology, slope,

width, depth, sediment

balance etc.

local morphology, bed forms,

islands, bank erosion etc.

sediment transport, grain

sorting, flow velocities,

initiation of motion UP-

SCALING

RIVER SCALING CONCEPT

boundary

conditions

analysis of total

catchment

analysis of key

sections

measurement /

modelling of key-

processes

suggestion

catchment-

management

results for

sectional scale

aggregation of

data for local

scale

possible reg.

consequences

discussion river

morphol. units

Habersack, 2000




Environment


New types of structures to improve

the sediment continuum




Environment


Sedimentationfushing

• 1987: 20.000 - 30.000 m³

• 1999: ~ 50.000 m³

• 2001: ~ 15.000 m³

dredging 3.000 – 4.000 m³

bedload / year

Optimisation of measures conc.

• Technical

• Economical

• Ecological points EU Projekt WARMICE

Habersack et al., 2001

Measures:

• ski jump

• improved bottom outlet

• bypass systems

• presedimentation area

• reservoir geometry

• reservoir managem…

Reservoir sedimentation




Environment


Optimization

0

20000

40000

60000

80000

100000

120000

140000

160000

0

1

2

3

4

5

6

7

8

0 1 2 3 4 5 6lo

st

mo

ne

y [

Eu

ro]

los

t en

erg

y p

rod

uc

tio

n

[Mio

kW

h]

flushing duration [days]

lost power productionlost income

0.0000

0.0050

0.0100

0.0150

0.0200

0 100000 200000 300000 400000

sedimentation [m³]

flu

sh

ing

eff

icie

nc

y F

e

( ) /o o i ie

o

V C VCF

V

ρ−=

0

20

40

60

80

100

9.5 10 10.5 11 11.5 12

stress index

Fis

ch

mo

rta

lity

[%

]

15 min peak 75 min peak total flushing duration

stress index = ln(Cs* t)

Habersack et al., EU project Warmice




Environment


Density current

(Morris & Fan, 1998)

ρ− −

− − −

= + −

+ − +

T T T

T T T

2 3 2

4 3 6 4 8 5

999,8395 6,7914 *10 9,0894 *10

1,0171*10 1,2846 *10 1,1592 *10

ρρρρw = ρρρρT + �ρρρρs

ρρρρs= C(1-1/γγγγs) * 10 –3

ρ

ρ ρ

ρ

=−i r

p

r

UF

gh

Calculation of depth at„Plunge-Point“





Environment



Reservoir management




Environment


Further examples

AUSTRIA

HU

NG

AR

Y

ITALYSLOVENIA

GERMANY

Drau River

Mur River

Danube River




Environment


Example Upper Drau River

� Aims� Stop of river bed degradation

� Improve ecological status

� Improve flood management




Environment


Oktober 2001Juni 2002September 2002Juni 2003Juni 2004Juli 2005Juli 2006Juli 2007September 2008

N

Morphodynamics 2001 to 2008 due to bed widening




Environment


Morphology1999 2002 2003 20072004

15%

22%

4%

14%

5%

14% 11%

25%

10%

21%

26%

32%33%

14%

22%

0%

5%

10%

15%

20%

25%

30%

35%

5.11.01 24.5.02 10.12.02 28.6.03 14.1.04 1.8.04 17.2.05 5.9.05

date

sid

ea

rm d

isc

ha

rge

40 m³/s 115 m³/s 420 m³/s40 m³s-1

115m³s-1

420 m³s-1




Environment


Bed level difference 2001-2007




Environment


EXAMPLE MUR RIVER




Environment


Distribution of Gravel Bars 1876 -

Existing Situation

1

10

100

1000

10000

100000

95100105110115120125130135River Kilometer

Are

a in

m²

1876

IST-Zustand

slope

Summenlinie ausgehend von 1977

-550 000

-500 000

-450 000

-400 000

-350 000

-300 000

-250 000

-200 000

-150 000

-100 000

-50 000

0

50 000

9498102106110114118122126130

Fluss-km

Volu

men [

m³]

1977-19801977-19831977-19861977-19891977-19921977-19951977-19981977-2000Profile

River km

Vo

lum

e [m

³]

Degradation since 1977

Major impacts on sediment supply AS WELL!




Environment


River Restoration at Gosdorf

• 1 km length restored

• Removal of bank protection structures

• Dredging of new side arms

• 150 000 m³ immediate sediment input

Measures:

Aims:mitigating channel incision by:

• added sediment

• further sediment input originating from riverbank erosion

• increased width – decreased transport capacity




Environment


13.02.2012

24

Example Danube East of Vienna




Environment


River bed degradation

W. Reckendorfer, R. Schmalfuss, C. Baumgartner, H. Habersack, S. Hohensinner , M. Jungwirth, F. Schiemer




Environment


Artificial bedload input

Schimpf, Verbund




Environment


Artificial bedload supply

Schimpf, Verbund




Environment


River bed development 2005-2009

Habersack, Liedermann, Tritthart, 2010

� 635.000 m³ bedload output without supply

� Mean bed level difference(Strom-km 1880,0 – 1921,0):

� 1,9 cm/year (with supply)

� 4,2 cm/ year (without supply)




Environment


Problems/Measures

Problems

Measures

River bed

degradation,

Habitat structure

Minimum water

depth, River bed

degradation

Sidearm reconnection

Riverbank restoration

Low flow river regulation

Gravel redeposition

Granulometric bed improvement

Ecology Navigation




Environment


Reduce riverbed erosion by adding larger gravel

sizes (40 – 70 mm) within the natural grain size

spectrum � Granulometric Bed Improvement

Original stage I stage II

25

cm

GS

V

Mix

ed

ma

teri

al




Environment


Improve navigation conditions, particularly during

low flow periods, by raising water levels using

modified groyne shapes and riverbed adjustments

existing groynes

modified groynes




Environment


13.02.2012

32Hauer & Habersack, 2006Fotos: donauconsult, via donau




Environment


Nationalpark Donauauen




Environment


River Monitoring

Monitoring

Habersack, H.M. & Laronne, J. B.

(2002), J. Hydraulic Engineering,

Vol. 128, No. 5, 484‐‐‐‐499.

Habersack, H., Hauer, C.,

Liedermann, M., Tritthart, M.,

(2008), Water 21: 29-31.

Habersack, H.M, Nachtnebel, H.-

P, Laronne, J. B. (2001), J.

Hydraulic Research, Vol. 39/2,

125-133.

Habersack, H.M. & Laronne, J.B.

(2001), Water Resources

Research, Vol. 37, No. 12, 3359-

3370.

Smart, G.M., Habersack, H.M.

(2007), J. Hydraulic Research,

Vol: 45 / Issue: 5, 661–673.

Habersack, H.M., Seitz, H.,

Laronne, J.B. (2008), J.

Geodinamica Acta, 21/1-2, 67-79.




Environment


35

AUSTRIAN BED LOAD CONVEYOR

flow direction

bed-load traps

Integrated Bedload Monitoring Dellach/Drau

processing unit

bridge Dellach/Drautal

river gauging

Helley-Smith sampler

suspended load measurement

flow velocity meter

40 hydrophonesbed-loadflap

radiotracers

Admodus Sonar

Seitz & Habersack, 2007




Environment


Seitz & Habersack, 2007




Environment





Environment


River Modelling

3D-Hydrodynamics Flow field

Particle Tracing Sediment transport

� Suspended sed., bedload

� Lagrange‘ modelling by particle tracing

� Euler modelling by new sediment transport model

� �� Habitat modelling

Tritthart, M; Liedermann, M; Schober,

B; Habersack, H (2011): J HYDRAUL

RES. 49(3) 335-344

Tritthart, M; Schober, B; Habersack, H

(2011): J HYDRAUL RES. 2011 49(3),

325-334

Tritthart, M., Liedermann, M.,

Habersack, H., (2009), River Research

and Applications, 25: 62-81.

Krapesch, G., Tritthart, M.,

Habersack, H., (2009), River Research

and Applications, 25: 593-606.

Habersack, H., Hauer, C.,

Liedermann, M., Tritthart, M., (2008),

Water 21: 29-31.

Hauer, C., Mandlburger, G.,

Habersack, H. (2009), River Research

and Applications, 25, 29-47.




Environment


Conclusions

� there exists a strong hierachical scale depending

relation concerning sediment transport � RSC

� many rivers have already reached or will reach in the coming years a critical state of morphodynamic development (e.g. river bed break-through)

� sediment continuum, transport and river morphodynamics play a central role in river management and need to be incorporated, from new hydropower types to river restoration

� we need to promote less design but more self forming river restoration or mitigated management procedures

� the second river basin management plan needs fundamental sediment research concerning processes and measures




Environment


13.02.2012

40

University of Natural Resources and Applied Life Sciences

Vienna

Department for Water, Atmosphere and Environment

Institute of Water Management, Hydrology and Hydraulic Engineering

Christian Doppler Laboratory for Advanced Methods in River

Monitoring, Modelling and Engineering

Univ. Prof. DI Dr. Helmut Habersack

Muthgasse 107, A-1190 Vienna, Austria

Tel.: +43 1 3189900 101, Fax: +43 1 3189900 149

[email protected], http://iwhw.boku.ac.at

Documents

Sediment management along rivers in Austria · Sediment management along rivers in Austria I Helmut Habersack ... bank erosion etc. sediment transport, grain ... measurement / modelling