Sediment management in the Danube River Basin

Igor Liška ICPDR

Danube River Protection Convention

29 June 1994, Sofia (Bulgaria)

Protection of water & ecological resources

Sustainable use of water

Reduce nutrients & hazardous substances

ICPDR coordinates implementation of EU Water Framework Directive & EU Floods Directive

Manage floods & ice hazards

Contracting Parties

Bosnia & Herzegovina

Serbia

Montenegro

Romania

Bulgaria

Rep. of Moldova

Ukraine

European Union

Germany

Austria

Czech Republic

Slovakia

Hungary

Slovenia

Croatia

Coordination Mechanisms

IT

CH

PL

MK

AL

DE AT

CZ

UA

MD

HU

SI RS

RO

SK

HR

BA

ICPDR

Co-operation Co-operation at sub-basin level: e.g. Sava

BG ME

ICPDR Delegations of Contracting Parties

River Basin Management

RBM EG

PM EG

MA EG

Flood EG

IMGIS EG

PP EG

ad hoc S EG

ad hoc Strategic

Pressures & Measures

Monitoring & Assessment

Flood Protection

Public Participation

Information Management & Geographical Information

System

APC EG Accident

Prevention/Control Task

Groups

ICPDR Secretariat

Stakeholder Involvement: 22 Observers

Sediments in WFD implementation WFD Art. 5 Report 2004

Sediment deficit in the Danube due to damming and regulation works reported.

It stimulated further discussion on sediments in DRB. Sediment Issue Paper 2006

Prepared by HU, RO and AT in cooperation with the Secretariat.

Addressed both quality and quantity. The issue of sediment deficit remained open.

2006 paper: Damming & sediment transport

Sediment accumulation in dams - extraction needed Gravel extraction 15 000 m3/a in Abwinden–Asten dam. 325 million tons of sediment accumulated in the Iron Gate between 1972 and 1994 filling 10% of the reservoir capacity.

Reduced sediment discharge leads to riverbed erosion Danube downstream Vienna - riverbed erodes at a rate of 2.0 – 3.5 cm/year. Downstream the Freudenau dam addition of 160 000 m3 bed load per year is required . Significant erosion downstream the Iron Gate.

2006 paper: Sediment balance

Sediment deficit in the Danube due to damming and regulation works.

No deficit of suspended solids reported in the upper Danube.

0 10 20 30 40 50 60 70 80

1900 1950 1980 2000

SPM in Issacea in million tons/year

Mercury in Sediments

JDS4R - Kachlet

JDS96L - Vilkova

0

0,5

1

1,5

2

2,5

3

3,5

4

050010001500200025003000River-km

[µg/

g]

Danube Tributaries

Sediments & ecology

The bottom sediments of lakes, streams, groundwaters

and wetlands host an enormous diversity of biota (more than 100,000 benthic invertebrate species, 10,000 species of algae and more than 20,000 species of protozoans and bacteria).

Species richness of freshwater sediment biota varies

considerably between wetlands (locally up to 1500 invertebrate species), lakes and streams (locally approximately 80 – 1000 species) and ground waters (locally 0 – 150 species).

WFD implementation

RBM Plan 2009 Sediments addressed as “other issue” (not SWMI). Sediment chapter was based on the 2006 Issue Paper and on the

WWF report on Assessment of the balance and management of sediments of the Danube waterway.

Sediment balance of most large rivers within the DRB can be characterised as disturbed or severely altered.

Hydropower plants in the upper Danube catchments trap almost 80-90% of the sediment bed load.

One third of the suspended load retained in the upper Danube while in the lower Danube the transport of suspended load currently reaches only 30% of the original amount recorded.

RBM Plan 2009

Conclusions & way forward There is an increasing discrepancy in the DRB between sediment

surplus in reservoirs and retention basins of torrent control works and sediment deficit in the remaining free-flowing sections. In combination with river channelisation, this leads to river bed degradation and a loss of morphodynamic structures with associated problems concerning ecological status.

To propose appropriate measures for improving the above mentioned situation, a sediment balance for the DRB has to be developed, including identification of possible consequences due to climate change (e.g. glacier retreat). Availability of sufficient and reliable data on sediment transport is a prerequisite for any future decisions on sediment management in DRB.

RBM Plan 2009

Conclusions & way forward Attention should be given to ensuring the sediment continuum

(improving existing barriers and avoiding additional interruptions). Additional investigations are needed to identify the significance of

sediment transport on the Danube basin-wide scale. River regulation works (e.g. to increase transport capacity)

contribute to river bed degradation. River restoration is of key importance for reducing degradation and improving morphodynamics, necessary for achieving good ecological status.

Dredging contributes significantly to the bed load deficit. It is therefore recommended that commercial extraction of sediments be prevented and that material dredged for maintenance be inserted back into the river.

WFD implementation

• Discussion on the integration of sediment management into RBM was held on an international level

• Recommendations to be made for a better inclusion of relevant sediment issues in future RBMPs.

Navigation

Ship traffic causes waves, which can disturb the reproduction habitats of fish, benthic invertebrates, other biota as well as de-root aquatic plants and also cause an unnatural suspension of fine sediments, leading to reduced light for plant and algae growth.

For the preservation/conservation of the ecological integrity of the Danube River, the basic needs is balanced sediment budget.

natural disturbances (e.g. floods, droughts) and associated sediment transport variations are among the key elements that constitute the basis for the highly dynamic nature of riverine landscapes and their biodiversity.

Joint Statement adopted by Danube Commission, ISRBC and ICPDR

Hydropower

Wik

iped

ia/G

FDL

Hydropower

Process ongoing within the ICPDR: in close

cooperation with the hydropower sector and all relevant stakeholders a broad discussion is ongoing with the aim of developing guiding principles on integrating environmental aspects in the use of existing hydropower plants, including a possible increase of their efficiency, as well as in the planning and construction of new hydropower plants

Recent developments

EU Danube Strategy PA4 Example of project - “To carry out an assessment for

restoration of the sediment balance in the Danube”. Transboundary solutions need to be found for the

problem of riverbed incision and the lack of sediment. Co-ordination within the framework of the Strategy will

help ensure identification and implementation of best solutions.

This is also an important project in relation to flood prevention.

• Project proposal on “Danube Sediment Management – Assessment for Restoration of Sediment Balance in the DRB” was drafted by AT, HU, RO RS, SK and DE and the Secretariat and submitted to the SEE Programme call in November 2011;

• The project received the Danube Strategy Letter of Recommendation due to its high relevance for the implementation of Priority Area 4 of the Strategy;

• In October 2012 the ICPDR Secretariat was informed by the project lead that the Danube Sediment Management project was officially rejected.

ICPDR Sediment Project

Project partners

Lead Partner: Budapest University of Techonology (BME)

AT: BOKU (co-lead), UBA, BMLFUW

HU: BME, VITUKI, VKKI, ÉDUKÖVIZIG

RO: NIMH, Apele Romane

RS: Institute Jaroslav Černi

SK: VUVH

DE: BfG

OBS: ICPDR, ISRBC, BEW

WP 0 Project preparation WP 1 Project management WP 2 Communication / Dissemination & PP WP 3 Data collection, analysis and harmonization WP 4 Composition of a sediment balance WP 5 Pressure and impact analysis WP 6 Solutions for improving sediment transport and establishing a dynamic balance in the DRB (inputs

to the programme of measures)

Project Work Packages

• ICPDR asked the lead countries together with the Secretariat – based on the existing project proposal – to work towards a revised project proposal to be submitted with other stakeholders (i.e. hydropower, navigation) to a future call of an adequate funding program seeking close cooperation with the RBM EG, other relevant EGs, the EUSDR (Pillar B, PA1a and PA2) and other potential stakeholders involved in sediment management;

• ICPDR concluded that a sound knowledge base is needed before the sediment issue paper of 2006 can be updated.

Future steps