120510 iasi morave river - albert schwingshandl

DI Albert Schwingshandl

riocom – Consulting Engineers

Siebensterngasse 31/2, A-1070 Wien. www.riocom.at

Restoration measures at Austrian-Slovakian border

section of Morava river Presentation at RESTORE - Workshop

10th May 2012,

Iasi, Romania

CONTENT

1. Introduction to the area

2. History of river training works at Morava river.

3. Development of fluvial morphology.

4. Sediment processes.

5. Effects on flooding processes.

6. Restoration measures.

7. Monitoring results.

Morava river has its source in North-East of Czech Republic at 1.275 m a.s.l.

INTRODUCTION TO THE AREA

Morava river has its source in North-East of Chech Republic at 1.275 m a.s.l.

at its lower reach it forms the border between Austria and Slovakia at a length of 70 kilometres(136 m a.s.l.)

Introduction to the area GEOGRAPHIC SITUATION

• discharge maximum in spring, minimum in autumn.

• nivo-pluvial discharge regime.

Introduction to the area HYDROLOGICAL-HYDRAULIC CHARACTERIZATION

flood (100 years return period) HQ100 1.400 m³/s

mean annual flood discharge HQ1 440 m³/s

bankfull discharge265 m³/s

mean water MQ 115 m³/s

low water NQ 33 m³/s

channel width 40 – 200 m,

mean width 70 m

mean slope 0,18 ‰

water depth (measured from MQ level) 2 – 6 m

velocity at MQ 0,8 m/s

Introduction to the area HYDROLOGICAL-HYDRAULIC CHARACTERIZATION

Introduction to the area RIVER MORPHOLOGICAL CHARACTERISTICS

before river training(aereal picture 1942 ))

initially meandering river course

initial bed slope 0,12 ‰

Objectives of river training works:Improvement of land use.

Reduction of high probability flooding.

Improvement of conditions for navigation.

After 1918: Border definition between CSSR and AT.

Main phases of construction works:1. phase 1911 to 1918: river mouth longitudinal structures March km 0-4,7.

2. phase 1919 to 1934: AT until 1925 woodenstructures for river bank protection; partial excavation of cut-offs.

3. phase 1935 to 1967: Revision of „General Project 1935“ -> detail projects (meander cut-offs, standard cross section .

HISTORY OF RIVER TRAINING WORKS

With the foundation Joint Technical Commission in 1931 Morava river training works got a new bilateral administrative basis

Example TRAINING WORKS MORAVA Cut-Off V

History of river training works

Source: Archiv der ehemalg. Marchbauleitung des Bundesstrombauamtes im Bundesministerium für Verkehr, Innovation und Technologie, Abteilung IV/W3.Digitale Reproduktion: DI Gerald Benz Photografische Bearbeitung:Mag. Elisabeth Beer

Upper core of Cut-off V.



Quelle: Archiv der ehemalg. Marchbauleitung des Bundesstrombauamtes im Bundesministerium für Verkehr, Innovation und Technologie, Abteilung IV/W3.Digitale Reproduktion: DI Gerald Benz Photografische Bearbeitung:Mag. Elisabeth Beer

Opening of the upper core of Cut-off V.



Quelle: Archiv der ehemalg. Marchbauleitung des Bundesstrombauamtes im Bundesministerium für Verkehr, Innovation und Technologie, Abteilung IV/W3.Digitale Reproduktion: DI Gerald Benz Photografische Bearbeitung:Mag. Elisabeth Beer

RESULTS OF RIVER TRAINING WORKS

Source: BEV 1941-42.Bearbeitung:riocom, A. Schwingshandl

1942

RESULTS OF RIVER TRAINING WORKS

Regulierungsgeschichte

Results:The river training which has beenimplemented in past century has changedthe fluvial morphology of Morava riversistematically and substantially,regarding layout, longitudinal profile and cross section geometry.

Kex data:17 cut-offs were built, the river course was shortened by 11 kilometres.

About 70% of the river banks arestabilized by engineering structures.

Standardization of the channel geometryand increase of the discharge capacity of the standard cross section, consequentlydecrease of lateral connectivity.

1995

Source: BEV

History of river training works RESULTS OF RIVER TRAINING WORKS

Meander XVIa.


Cut-off section IV(concave bank already with restoration measures).


Still, high potential for restoration, due to partly low intensity of usesmost important lowland river ecosystem in Austria

Meadow near Marchegg

19941994 RAMSAR conceptRAMSAR concept

19951995--9797 MARTHA95 river development schemeMARTHA95 river development scheme

19991999--20022002 LIFE pilot restoration project MUFLIFE pilot restoration project MUF

20032003--20052005 MUF monitoringMUF monitoring

20042004--20062006 BGM Bilateral General ProjectBGM Bilateral General Project

20112011--20132013 LIFE project, MORE (ETZ)LIFE project, MORE (ETZ)

Introduction to the area RIVER RESTORATION PLANNING PROCESS

0,0

0,5

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Bordkantenentfernung [m]

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lere

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filtie

fe [m

]

Profilgeometrie vor Regulierung

CROSS SECTION GEOMETRY

B = 72 -83 m, T = 3,1 bis 3,6 m

B = 64 -99 m, T = 1,9 bis 2,7 m

B = 84 -112 m, T = 1,5 bis 1,9 m

Situation before river training shows a wide range of cross section geometry.

Quelle: Erstellung von wasserwirtschaftlichen Planungsgrundlagen für die Ö-SK Marchgrenzstrecke. riocom, G. Benz, A. SchwingshandlIm Auftrag: via donau – Österr. Wasserstraßen- Gesellschaft mbH.

Development of fluvial morphology

0,0

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Bordkantenentfernung [m]

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filtie

fe [m

]

Profilgeometrie vor RegulierungProfilgeometrie nach Regulierung

CROSS SECTION GEOMETRY

B = 60 – 80 m, T = 2,8 -3,8 m

By training measures a standardized profile was put in place.

B = 72 -83 m, T = 3,1 bis 3,6 m

B = 64 -99 m, T = 1,9 bis 2,7 m

B = 84 -112 m, T = 1,5 bis 1,9 m

Situation before river training shows a wide range of cross section geometry.


STANDARDIZATION OF CHANNEL GEOMETRIE


This standardizing of the channel geometry also means, that over long sections a bank levee was constructed.This levee mostly is higher than the sourrounding flood plain and therefore builds a barrier for frequent inundation. Moravka

Zaya

DEVELOPMENT OF RIVER BED ELEVATION


Mal

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Zaya

Thay

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D II

D II

I - V

II

D IX

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D X

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D X

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XVIII

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010.00020.00030.00040.00050.00060.00070.000Stationierung [m]

Sohl

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[m.ü

.A.]

Sohlhöhe 1908

Mean river bed elevation



Mittlere Sohlhöhen

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Sohlhöhe 1908Sohlhöhe 1934



Mittlere Sohlhöhen

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ina

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Thay

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D II

D II

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II

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D X

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010.00020.00030.00040.00050.00060.00070.000Stationierung [m]

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[m.ü

.A.]

Sohlhöhe 1908Sohlhöhe 1934Sohlhöhe 1956/58



Mittlere Sohlhöhen

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ina

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Thay

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D II

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130131132133134135136137138139140141142143144145146147148149150

010.00020.00030.00040.00050.00060.00070.000Stationierung [m]

Sohl

höhe

[m.ü

.A.]

Sohlhöhe 1908Sohlhöhe 1934Sohlhöhe 1956/58Sohlhöhe 1988/95



Mittlere Sohlhöhen

Mal

ina

Wei

denb

ach

Zaya

Thay

a

D II

D II

I - V

II

D IX

- XI

I

D X

III

D X

IV

D X

V

D X

VI -

XVIII

Mar

cheg

g

Bau

mga

rten

Ang

ern

Dür

nkru

tHoh

enau

130131132133134135136137138139140141142143144145146147148149150

010.00020.00030.00040.00050.00060.00070.000Stationierung [m]

Sohl

höhe

[m.ü

.A.]

Sohlhöhe 1908Sohlhöhe 1934Sohlhöhe 1956/58Sohlhöhe 1988/95Sohlhöhe 2006

SEDIMENT PROCESSES

SUSPENDED SEDIMENT MODELLING

sediment processes

The aim is to gain knowledge on the sedimentation processes in the floodplains.

Results of long-term modelling (31 years).

Source: Num. 2D-Modell für March und Thaya in A, SK und CZ. ARGE riocom-IB Humer-AquasoliIm Auftrag: via donau und Land NÖ-WA2

SUSPENDED SEDIMENT MODELLING

sediment processes

Results of long term modelling (31 years).

Section: Morava at Zaya river mouth

Quelle: Num. 2D-Modell für March und Thaya in A, SK und CZ. ARGE riocom-IB Humer-AquasoliIm Auftrag: via donau und Land NÖ-WA2

MORPHOLOGICAL DYNAMICS: EROSION - SEDIMENTATION

sediment processes

The digital terrain model (laserscan 2007; 3d-Shade) how the balance between sedimentation and erosion is proceeding in a dynamic river system:

by erosion on the concave bank the river „consumes“ the natural bank levee and migrates, and leaves behind a natural bank levee on the convex bank.

Grafik Quelle: Num. 2D-Modell für March und Thaya in A, SK und CZ. ARGE riocom-IB Humer-Aquasoli. Im Auftrag: via donau und Land NÖ-WA2

MORPHOLOGICAL DEVELOPMENT

Event 1: Morava river morphology was shifted into an new system stage by the river training works(singulary event).

Process 1 River bed deepening: in lage sections of Morava river the channel bed deepened significantlybetween the river training and ca. 1990 (Continous process … +/- terminated).

Process 2: sedimentation along river bank, while riverlayout is fixed, causes a successive raisening of riverbank (Continous process … ongoing).

Entwicklung der Gewässermorphologie

Für das morphologische Gesamtsystem der March stellt sich in Hinblick auf die Zukunft die essentielle Frage: kommt (u.a.) durch das Fortschreiten von Prozess 2 (Sedimentation) in einer bestimmten Phase/Abschnitt wieder Prozess 1 (Sohleintiefung) in Gang ?

Due to morphological changes the bankfull discharge is exceeded less frequently. Discharges between NQ and HQ1 remain within the bankfull cross section.

EFFECTS OF MORPHOLOGY ON FLOODING PROCESSES

Quelle: Hydromonitoring für die Maßnahmen an der March in Marchegg Km 15-25. riocom, A. SchwingshandlIm Auftrag: Wasserstraßendirektion / via donau

EFFECTS OF MORPHOLOGY ON FLOODING PROCESSES








6. Restoration measures (-> pres.#2).


INTERDISCIPLINARY MONITORING

The main aim of the Project at river Morava was to• Re-structure the river banks• Increase the lateral connectivity with wetland

areas• Partly re-connect cut-off meanders

After the implementation of measures, the success of the measures was assessed within a interdisciplinary monitoring (2003-2005).

Eight different groups of organisms were chosen as bioindicaors to cover the whole range of effects of the measures on the entire river stretch and the backwaters

Evaluation summary

type description

birds

amphibians

fish

makrozoo-

benthos

dragonflies

macrophytes

phytobenthos

vegetation

A1.1 Total removal of outer bank protection with preventive erosion limits + +/- + + +

A2 Partial removal of river protection at outer bank + + + + + +

B3* Deposition of material at inner bank, partial removal of bank protection + + + + + + +/- +

B4* Deposition of material at inner bank + + + + +

C1 Reactivation of former gully systems + +/- +/- +/- + +

D1 Reconnection of meander systems from downstream +/- +/- + + +/- +/- +

D2 Initiations of outer banks in preparation to upstream meander opening +/- +/- +/- +/-

E2 Relocation of bed sediments + + +

E3 Installation of woody structures +/- + +

F1 Partial removal of river protection and reshape to mean-flow groins +/- + + + +

Initiation of steep flanks at the outer bankby (partially) removing bank protection

Creation of sediment banksat the inner bank

Reactivation and integration ofmeander and gully systems

Installation of woody structures

BIRDS Indicator for river-bank connections

Steep concave banks are important breeding places for some birds especially for the kingfisher

The study at Morava river showed that also artificially built river sediment banks were settled by some species (e.g. the little ringed plover)

A minimum size of 400m2 bank area should be aspired

Lateral connectivity increases the habitat quality of many aquatic birds

Structual diversity demonstrably has a positive influence on species diversity

[TEUFELBAUER & ZUNA-KRATKY, 2004, 2005, 2006]

AMPHIBIANS Indicator for river-floodplain connections

The artificial built flat and muddy river banks at the Morava river due to perfect summer habitats for juvenile frogs

Wetlands and flooded meadows are significant spawning grounds for amphibian invertebrates

Therefore the lateral connectivity is very important for these animals.

[WARINGER-LÖSCHENKOHL, 2005]

FISH Indicator for the ecological situation of the whole river system

The arising results of removing bank protections are pools which are suitable habitats for many adult fish.

Furthermore structural diversity and wooden nests increased the number of individuals of the dominant fish species in the Morava river, like carp, catfish and bream.

Flat overflowed banks (riffles) have positive effects on rheophile river fauna

Overall 36 (2004) different species were located with a high ratio of endangered fish.

The reactivation of former gully sytems and side channels increased the number of individuals of indifferent and stagnophil species.

[SPINDLER & WINTERSBERGER, 2003, 2004, 2005]

MACROZOOBENTHOS Indicator for waterbody structures and organic load

The removal of the river bank protection in the Morava river mainly reduced the individuals which are not typical for that location.

In fact the typical local species creates an increasing number of individuals.

The flattening of concave banks leads to high biocenotical ratio. Flat banks are very essential habitats for the characteristical macrozoobenthos invertebrates in the Morava river.

Also the connectivity to former gully systems and side channels led to a higher biocenotical ratio and reduced the number of untypical individuals.

The artificial installation of woody structures showed also positive effects.

[GRAF & BLOCH, 2005]

DRAGONFLIES Indicator for structural heterogenity and lateral interaction of the river with its forelands

50% of the identified taxae are endangered according to the “red list” of Lower Austria.

A high portion of the found taxae are sensitive and serve therefore as a good indicator.

Removal of bank protection has a positive impact on the dragonfly- fauna.

Created sediment banks are used by dragonfly larvae and therefore essential habitats.

These banks already show a fully developed coenosis of certain species as well as a high density of taxae.

The implementation of woody structures has a positive impact. The increase in structures is evaluated positively.

[SCHULTZ, 2005]

MACROPHYTES Indicator for river structures and lateral connectivity

80 taxae could be identified during the field investigation29 taxae of these are listed no the “red list”The aquativ vegetation can therefore be accounted as very

specious and valuable.

The removal of riverbank protection created habitats for pioneer vegetation.

Increased stream curvature and stream velocity variability create a range of new habitats for a range of endangered taxae.

New sediment banks provide habitats for site-specific plants.The created water-foreland interaction zones induced a

significant increase in taxae.The dimension of measures set had most influence on the

aquatic vegetation.

[PALL & MOSER, 2005]

PHYTOBENTHOS Indicator for the contaminant load of the water body

118 taxae could be identified during the field investigation.Only two taxae of these are listed on the “red list”.Region-specific reference-taxae made up to 40% of the total.No significant change, caused by the set measures could be

identified. This goes well with experiences from other locations.

Structural changes therefore don’t have a significant impact on water quality.

[PFISTER, 2005]

VEGETATION Indicator for the change in interaaction with the forelands on different sites

21 taxae of neophytes could be identified in the investigation area

The high spatial and temporal variability of the outer banks are evaluated as positive indicator

The presence of the winged saltbush (Graumelde), on created sediment banks can be seen as a great success.

The permanent succession furthermore leads to a constant change in vegetation

The change in water supply of the surrounding areas induces a gradual change in the vegetation ecotype.

The reactivation of meanders and gullys therefore is seen as a positive aspect.

The reinstalled interaction of the river with the foreland allows to reestablish the typical potamal flood plain ecosystem

[LAZOWSKI, 2007]

OVERALL CONCLUSIONS

The analysis shows that for most of the biota the implementation of measures lead to an improvement of the habitat quality.

Especially the interaction between river and wetland improved significantly.

The results of the study are important for river restoration projects of lowland rivers and will provide useful information for the implementation of the program of measures according to the EU Water Framework Directive

THANKS FOR YOUR ATTENTION

Acknowledgements to clients and partners

via donau –Österr. Wasserstraßen-Gesellschaft mbHAustrian Waterways Assoc.

Regional Government of Lower Austria –

UBA Austrian Environment Agency

and all project partners for excellent collaboration.!

riocom - Albert Schwingshandl [email protected]

120510 iasi morave river - albert schwingshandl

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