DELIVERABLE 2.1.2 OVERVIEW OF … · OVERVIEW OF INFRASTRUCTURE ADAPTATION MEASURES AND RESULTING DISCHARGE SCENARIOS PUBLIC ... CIP Continuous Improvement ... with the following

DELIVERABLE 2.1.2

OVERVIEW OF INFRASTRUCTURE ADAPTATION

MEASURES AND RESULTING DISCHARGE SCENARIOS PUBLIC

Report for:

European Commission Directorate-General for Energy and Transport

1049 Brussels

January 10th, 2012

Authors: Markus Simoner Juha Schweighofer Bastian Klein Enno Nilson Imke Lingemann

ECCONET - Effects of climate change on the inland waterway transport network – contract number 233886 – FP7 2

Table of contents

ABBREVIATIONS ............................................................................................................................................... 3

1. INTRODUCTION....................................................................................................................................... 4

2. SYSTEM ELEMENTS OF THE WATERWAY INFRASTRUCTURE ..................................................... 5

3. THE AUSTRIAN SECTION OF THE DANUBE ..................................................................................... 8

3.1 CHARACTERISTICS OF THE AUSTRIAN SECTION OF THE DANUBE WATERWAY AND INTERNATIONAL

WATERWAY PARAMETERS.....................................................................................................................................................8 3.2 WATERWAY MAINTENANCE ..............................................................................................................................................10 3.2.1 Surveying and planning.....................................................................................................................................................12 3.2.2 Dredging...........................................................................................................................................................................13 3.2.3 Provision of information ....................................................................................................................................................15

3.3 RIVER ENGINEERING WORKS ...........................................................................................................................................16 3.4 ASSESSMENT OF WATERWAY-MAINTENANCE COSTS IN THE FUTURE .......................................................................18

4. THE GERMAN SECTION OF THE DANUBE BETWEEN STRAUBING AND VILSHOFEN ......... 21

4.1 CURRENT CONDITIONS ......................................................................................................................................................22 4.2 VARIANT A: FURTHER OPTIMIZED STATUS QUO ...........................................................................................................23 4.3 VARIANTS C AND C2.80: ONE BARRAGE VARIANTS .....................................................................................................24 4.4 SUMMARY OF THE DIFFERENT VARIANTS .......................................................................................................................27

5. THE RHINE RIVER BETWEEN MAINZ AND GOAR (SECTION “KAUB”) .....................................28

6. CONCLUSIONS .........................................................................................................................................30

REFERENCES....................................................................................................................................................32


Abbreviations

CIP Continuous Improvement Process

fif Fairway within the fairway

ECDIS Electronic Chart Display and Information System

GlQ Gleichwertiger Abfluss; long-term mean discharge exceeded on all but 20 ice-free days per year;

gives GlW

GlW Gleichwertiger Wasserstand; Equivalent Water Level

HNN Haut Niveau Navigable; French abbreviation for HNWL

HNQ Discharge reached or exceeded on an average of 1% of days in a year; gives HNN (HNWL, HSW)

HNWL Highest Navigable Water Level

HQ100 High-water discharge with a statistical recurrence interval of 100 years

HSW Höchster Schifffahrtswasserstand; German abbreviation for HNWL

LNWL Low Navigable Water Level

LRWL Lowest Regulated Water Level

MQ Mean Discharge

MWL Mean Water Level

MW Mittelwasser; German abbreviation for MWL

NtS Notices to Skippers

RNQ Discharge reached or exceeded on an average of 94% of days in a year; gives LNWL (RNW)

RNW Regulierungsniederwasser; German abbreviation for LNWL and LRWL


1. Introduction

The general function of waterway infrastructure is to enable safe and economically viable navigation on a

river. The fairway is a central element of the waterway infrastructure, besides other elements e.g. locks. In general, it can be characterized as a defined area in a river which has to be maintained by the respective

responsible waterway authorities.

International agreements define fairway parameters in order to enable inland navigation based on the same

standards. In general, the waterway infrastructure is public property, and it is the duty of national waterway authorities to establish and maintain the fairway in correspondence to these international conventions and

agreements.

Climate change is neither a new phenomenon nor a discontinuous function, and rivers are complex living

systems featuring continuously changes. Waterway management authorities are obliged to continuously monitor water discharge patterns on the time axis and adapt their waterway management-related activities

accordingly in the case of altered conditions, be it due to climate change, hydro-morphological alterations or erosion processes of the riverbed.

Extreme weather events have been occurring in the past and today. Waterway administrations can and must

prepare dedicated adaptation strategies for the short-, medium and long-term perspective. Whereas adaptation

strategies for the short-term perspective can be implemented immediately in reaction to changing water discharge patterns, medium and long-term strategies need some time to be implemented, and they should

include different sets of measures in order to provide adequate responses to different climate change scenarios.

This report aims at giving an overview of adequate options for infrastructure adaptation to climate change ensuring the provision of internationally agreed navigation conditions also in the future. In particular measures

related to waterway maintenance and river engineering will be considered complemented by a discussion on expected future costs of waterway maintenance using the example of the Austrian Danube.


2. System elements of the waterway infrastructure

The starting point for the identification of general adaptation options regarding waterway infrastructure is a

clear description of the relevant system elements which have an influence on the fairway. Based on an analysis of these system elements, general adaptation options will be described including concrete and practical

examples of measures for waterway authorities.

The central waterway infrastructure element is the fairway. Generally speaking, the fairway is established by

means of river engineering elements, e.g. groynes, training walls and rip-rap. It is maintained via maintenance works including surveying, dredging and information provision activities. These two principal elements shall

ensure the internationally defined navigation requirements, fairway dimensions, on a certain river section at low water conditions. Changing climatic conditions would alter the temporal distribution of the water

discharge of the respective river throughout the year, and thus, they will have directly an effect on the

navigability of the corresponding river stretches.

Basically, the available water depths and widths of the fairway are defined through the interaction of three elements: the river's geometry and hydromorphology, the water discharge and the waterway infrastructure

(river engineering elements).

Thus, the first step is a clear identification and description of these relevant system elements:

Figure 1: Relevant system elements of the fairway.


These three elements are characterized by the following features:

• River:

o General geometry/dimensions, e.g. width and depth; o General characteristics of the river stretch: impounded or free-flowing;

o Hydromorphological characteristics, e.g. incline, flow velocity, riverbed material, or sediment

balance; o Dimension/proportion of the fairway as a part of the river.

• Waterway infrastructure:

o Position and dimensions of river engineering elements, e.g. groynes, training walls or rip-rap

in the river, especially in free-flowing sections; o Position of weirs/river power plants in impounded sections.

• Water discharge: o Temporal distribution of water discharge, e.g. over a reference period of one year, at selected

cross sections of the river.

The effectiveness of the river engineering elements, and thus the availability of certain navigation fairway

parameters at low water conditions is the result of the interaction between these three elements which can be described as follows:

• River – waterway infrastructure

o The basic river characteristics, e.g. geometry or hydromorphological processes, directly influence the effectiveness of the river engineering elements;

o River engineering elements have an impact on the hydromorphological characteristics, e.g. sediment transport or water flow velocity, of the river and can also influence its general

dimensions, e.g. width and depth;

o Hydromorphological processes in the river, e.g. erosion processes of the riverbed, can lead to an alteration of the relative position of the river engineering elements, e.g. groynes, training

walls, and rip-rap, within the river and thus influence their effectiveness.

• Waterway infrastructure – water discharge

o The temporal distribution of the water discharge influences the effectiveness of the river engineering elements. Thus, an altered temporal distribution of the water discharge, e.g.

caused by climate change, may affect the effectiveness of the river engineering elements and thus influence the available fairway parameters in case of low water conditions, especially in

free-flowing sections.

• River – waterway discharge

o The temporal distribution of the water discharge can also influence the basic characteristics

of the river, especially in free-flowing sections, e.g. the river geometry or its hydromorphological characteristics, e.g. sediment transport, and water flow velocity.

As a third step in the analysis, the basic intervention possibilities by waterway administrations with respect to

the three general system elements are described:

• The system element "water discharge" cannot be directly influenced or changed by waterway administrations, e.g. through human interventions. Possible future changes in the temporal

distribution of water discharge, e.g. caused by climate change, can only be predicted in a limited way,

with the following general problem: The farther the forecast on the time axis, the more insecure is the expected result.


• The system element "river" characterised by its geometry and hydromorphological characteristics can

only be influenced or changed in a limited way by waterway administrations. Such changes may result

from large infrastructure projects, e.g. structural changes due to the construction of dams, or they can also be the result of continuous and long-term processes like hydromorphological alterations due to

erosion.

• The system element "waterway infrastructure" comprising groynes, training walls, and rip-rap is

directly created by waterway administrations, i.e. a result of human intervention. The effectiveness of

river engineering elements can be measured and can also change in the course of time. Furthermore, continuous maintenance works, e.g. dredging, constitute a non-structural measure carried out by

waterway administrations in order to maintain the required fairway parameters. Related to improved coping with low-water events, effective dredging works of shallow sections are best carried out before

the occurrence of low-water periods.


3. The Austrian section of the Danube

In the following measures for coping with extreme weather events and climate change impacts are discussed.

The discussion is focussed on the Austrian stretch of the Danube. Nevertheless, in principle, most conclusions drawn will be valid for other European waterways, too, in particular the entire Danube.

3.1 Characteristics of the Austrian section of the Danube waterway and international waterway parameters

The Austrian section of the Danube waterway has an entire length of 350.45 km, whereof 21.38 km represent

the border with Germany (rkm1 2223.150 – 2201.770) and 7.56 km the border with Slovakia (rkm 1880.260 – 1872.700). The remaining 321.51 km (rkm 2201.770 – 1880.260) are on Austrian territory.

The Austrian section of the Danube can be characterized as follows:

Length: 350.45 km Width: about 300 m on average

River power plants, locks: 10 (including lock Nussdorf on the Danube Canal in Vienna) Free-flowing sections: Wachau: rkm 2038 – rkm 2014 (=total of 24 km);

East of Vienna: rkm 1921 – rkm 1869 (=total of 52 km)

Fords/shallow sections: 35

The characteristics of sediment transport in the Austrian section of the Danube are presented in the table below.

Table 3.1: Characteristics of sediment transport in the Austrian section of the Danube.

Dominant transport Material and diameter

Free-flowing sections Bed load Gravel (0 – 120 mm)

Impounded sections Suspended load Clay (21–31%), silt (65–73%),

sand (2–7%)

The average water discharges of the Austrian Danube are shown for the cross section Vienna in Table 3.2.

Table 3.2: Average water discharges of the Danube at the cross section in Vienna in Austria.

Parameter / facility Danube Danube Canal Total

Low Navigable Water Level LNWL96 (RNW96)2 830 m³/s 70 m³/s 900 m³/s

Mean Water Level MWL96 (MW96)3 1700 m³/s 190 m³/s 1890 m³/s

Highest Navigable Water Level HNWL96 (HSW96)4 5070 m³/s 200 m³/s 5270 m³/s

100-year discharge (HQ100) - - 10400 m³/s

1 rkm = river kilometre 2 Water level reached or exceeded on an average of 94% of days in a year (i.e. 343 days) over a reference period. Often

denoted also as Lowest Regulated Water Level LRWL. Derived from long-time discharge information. 3 Water level corresponding to the arithmetic mean of the average annual discharge volume for an observation period of

several years (e.g. 30 years). 4 Water level reached or exceeded on an average of 1% of days in a year (i.e. 3.65 days) over a reference period.


Regarding the waterway parameters of the Austrian Danube the following international conventions and

agreements are relevant:

• the Recommendations of the Danube Commission;

• the provisions of the European Agreement on Main Inland Waterways of International Importance

(AGN).

The Danube Commission recommends the following parameters for the Austrian Danube section (Table 3.3).

Table 3.3: Fairway parameters and headrooms under bridges and power lines recommended by the Danube

Commission for the Austrian Danube.

Depth recommendation (at LNWL)

In impounded sections 27 dm gravel, 28 dm rock

Wachau (rkm 2038 – rkm 2014) 20 dm gravel, 21 dm rock

East of Vienna (rkm 1921 – rkm 1869) 25 dm gravel

Width recommendation

Inn confluence – Vienna (rkm 2225.32 – rkm 1920.30) Free-flowing 120 m Reservoirs 150 m

Vienna – Devin (rkm 1920.30 – rkm 1880.26)

Rock 75 m

Gravel 120 m

Curvature recommendation

Jochenstein – Krems (rkm 2203.33 – rkm 2001.00) Free-flowing 350 m

Reservoirs 350 m

Krems – Vienna (rkm 2001.00 – rkm 1920.30)

Free-flowing 800 m Reservoirs 900 m

Vienna – Devin (rkm 1920.30 – rkm 1880.26)

Free-flowing 800 m

Reservoirs 1000 m

Headroom under bridges

Upstream of rkm 1920.30 8 m at HNWL

Downstream of rkm 1920.30 10 m at HNWL

Headroom under power lines

General 16.5 m at HNWL

Up to 110 kV5 = 19 m at HNWL

Over 110 kV = 19 m + 1cm/kV at HNWL

Further relevant waterway parameters for the Danube are specified in the AGN – the "European Agreement

on Main Inland Waterways of International Importance". The AGN was first published by the United Nations Economic Commission for Europe (UNECE) in 1996 and is periodically revised (last time in 2008).

It contains technical and operational parameters for the planning, extension and maintenance of Europe's network of inland waterways.

In order to monitor the current status and thus the development of the network and its parameters, the

UNECE maintains an "Inventory of Main Standards and Parameters of the E Waterway Network", the so

called "Blue Book", which was first published in 1998. A first revised edition appeared in 2006, the third edition is scheduled for spring 2012.

5 kV = kilovolt


The "Blue Book" classifies the Austrian section of the Danube as an international waterway of class VIb. The

following table provides an overview on waterway parameters as stipulated by the AGN.

Table 3.4: Waterway parameters stipulated by the AGN.

Regarding the technical and operational parameters of the Austrian section of the Danube waterway, the

AGN recommends a minimum draught of 2.5 metres for vessels on a minimum of 300 days per year.

3.2 Waterway maintenance

In its function as the competent waterway management authority via donau – Österreichische Wasserstraßen-Gesellschaft mbH carries out its responsibilities concerning waterway administration and maintenance.

Waterway maintenance activities are embedded in a complex framework of various legal, organisational and

technical conditions and interdependencies, which are displayed in Fig. 3.2 (see next page).

In order to better understand and evaluate the possible adaptation measures in the field of waterway

management a short overview is given on the basic elements, which are surveying, dredging and the provision of information (Fig. 3.1).

1

Surveying

1

Surveying

2

Dredging

2

Dredging

�

Information

�

Information

Figure 3.1: Main system elements of modern waterway management.

Figure 3.2: Legal, organisational and technical framework conditions relevant to waterway maintenance.


The basic elements of waterway maintenance are interdependent and interconnected in a logical context,

therefore the interactions between these elements are subsequently described as "waterway maintenance cycle"

being described in the following:

(1) The first step in waterway maintenance is the continuous monitoring and general bathymetrical survey of the fairway in order to identify shallows. Detailed bathymetrical surveys are then undertaken for shallows

which are the basis for the planning and monitoring of the subsequent dredging measures.

(2) Dredging works have to be contracted and assigned. Right before and after dredging measures in the

fairway, the intervention areas are surveyed to enable monitoring of the works as quality control.

(3) Dredging measures are followed by in-house documentation and external communication to target groups,

e.g. shipping companies, assuring continuous information on the current status of the fairway infrastructure. The provision of information is achieved by means of various channels, e.g. Notices to Skippers, the website

of the Donau River Information Services (DoRIS), information at locks or Inland ECDIS charts.

Figure 3.3: Interactions of main system elements: The waterway maintenance cycle.

3.2.1 Surveying and planning

Surveying activities are the basis for a modern waterway infrastructure management: It is of crucial importance

to know the current status of the fairway during the year in order to be able to plan and execute the necessary maintenance dredging measures. In addition to that, surveying results also serve customers (masters of inland

waterway vessels) as valuable information for the optimal navigation on demanding sections of the fairway.


Thus, via donau houses a separate department which is exclusively dedicated to surveying activities. As a basic

principle, continued investment in modern surveying equipment (vessels and surveying systems) is made in

order to be able to continuously survey the status of the riverbed. The two free-flowing sections of the Danube in Austria are surveyed twice a year on their entire length. In addition to that, shallows are surveyed at

least on a monthly basis. In the case of decreasing water levels, the interval of surveying activities is reduced to two weeks, and in periods with low water levels shallows are surveyed on a weekly basis. Thus the effects of

changing water discharges on the waterway infrastructure are continuously measured and evaluated.

The following figure displays an example of a multi-beam surveying result in the free-flowing section of the

Wachau.

Figure 3.4: Example of a multi-beam survey result in the free-flowing section of the Wachau.

3.2.2 Dredging

Dredging activities in the fairway are essential in order to ensure the fairway parameters as stipulated in the "European Agreement of Main Inland Waterways of International Importance" (AGN) and the

Recommendations of the Danube Commission. As a basic principle, via donau is committed to continuously

maintain a fairway depth of 2.5 metres below Low Navigable Water Level (LNWL) in the two free-flowing sections of the Danube in Austria.

In order to optimize dredging activities throughout the year, via donau has set up a general categorization of

shallow sections. Table 6 below lists the 35 shallows in the two free-flowing sections: Wachau and to the east

of Vienna, and it contains information whether the shallow area is located in the middle of the fairway (ford, "Furt") or at one of the fairway boundaries ("Haufenrand"). Out of these 35 shallows, 17 shallows have been

identified which are in need of close monitoring as they pose or tend to pose obstacles for navigation.


Table 3.5: Shallows in the free-flowing sections of the Austrian Danube. Source: via donau.

The river sections of the Austrian Danube in which the 17 "critical" shallows are located have also been indicated in the Austrian Inland ECDIS charts as "caution areas". via donau is continuously monitoring the

current status of these shallows in order to be able to plan and execute the necessary dredging measures right

on time.

Furthermore, via donau is currently elaborating a new dredging strategy in order to optimize the effectiveness of its dredging activities. As a basic principle, the most critical shallows shall be dredged at the beginning of a

potential low-water period. According to long-time statistical time series, low-water periods on the Austrian

section of the Danube normally start at the beginning of autumn. Fig. 3.5 (next page) visualises this objective, which shall be implemented for the first time in the autumn of 2011.

The prioritisation of dredging activities within a defined time frame at the beginning of the annual low-water

period constitutes one of the most important measures foreseen in via donau's new fairway maintenance

strategy. Every year, the most "critical" shallows in the two free-flowing sections of the Danube in Austria will be dredged starting from the beginning of September. This dredging strategy is in line with the current water

discharge pattern on the Austrian part of the Danube River. If low water periods will change with regard to their seasonality due to climate change in the future, via donau would accordingly adjust the above mentioned

dredging strategy, comprising one cost-efficient adaptation measure to possible climate change impacts.

Apart from the introduction of this time frame and by taking the frequently fluctuating water levels of the

Upper Danube duly into account, via donau also foresees the possibility of dredging activities outside of the annual time frame set, e.g. in the case of a flood during the winter. Typically, the riverbed dramatically changes

in the course of such an event which cannot be foreseen or planned in advance. Thus, via donau also provides for the possibility to react immediately after such events.


Water levels at the gauge Wildungsmauer 2009

Dai

ly a

vera

ge

wat

erle

vel[

cm]

Figure 3.5.: Water levels at the gauge Wildungsmauer. Timeframe for most urgent dredging activities. The y-

axis denotes the average daily water level at the gauge Wildungsmauer on the Austrian Danube in the year 2009. The x-axis denotes the days and months of the year 2009. RNW96 = LNWL96. RNW96+50 =

LNWL96+50 cm. MW = MWL96. HSW96 = HNWL96. HSW96+90 = HNWL96+90 cm.

3.2.3 Provision of information

The third important element of a modern waterway management system is the provision of up-to-date and precise information to target groups. This includes both information on all internal processes and procedures

related to waterway management and information to external users of the waterway. The optimization of the

processes needed for providing external information is one of the most important elements of the waterway management system at via donau.

Apart from already well-known and established information tools such as Notices to Skippers or Inland

ECDIS charts, via donau is also investing in modern information tools via its websites. One element are

forecasts of water levels at relevant water gauges, which are currently only available as one-day forecasts. By means of a new project which has just been started, via donau intends to extend its water level forecasts to a

time period of three days.

Another crucial element is information on the current status of shallows in the free-flowing sections of the Austrian Danube which is available online on the DoRIS website. Besides numeric information on available

fairway depths, via donau is also publishing its most recent surveying results related to shallows in graphical

format in the form of longitudinal profiles, so-called track plots (Fig. 3.6).


Figure 3.6: Track plot of fairway depth information of a shallow, available at the DoRIS website. Source: via donau.

This information shall enable users of the waterway to gain a comprehensive overview on the current status of

shallows in the fairway. It enables masters to navigate in the deeper areas of the fairway, thus assisting in

improving the efficiency of the transport by increasing the possible draught of their vessels. In case of an unfavourable development of the water discharge the use of deeper areas of the fairway will be of crucial

importance for the economic viability of the inland waterway transport sector. Therefore, dedicated and detailed graphical information on the current status of the fairway can be considered as a pro-active adaptation

measure with regard to potential climate change.

3.3 River engineering works

On the Austrian Danube the main river engineering constructions in the free-flowing section of the Wachau valley are finished. Currently, the free-flowing section of the Danube between Vienna (Freudenau power

plant) and the Austrian-Slovakian border (rkm 1921.05 – 1872.70) constitutes a substantial bottleneck for inland waterway transport. In addition to several shallows, this waterway stretch is characterized by a

continued riverbed erosion rate of 2.0 up to 3.5 cm per year. Therefore, the Federal Ministry of Transport,

Innovation and Technology (bmvit) and via donau initiated the "Integrated River Engineering Project on the Danube to the East of Vienna" in order to improve fairway conditions and eliminate ecological deficits in this

stretch of the Danube. For this purpose, the implementation of a combination of different river engineering and ecological hydro-engineering measures is planned comprising:

• Granulometric riverbed stabilization,

• Low water regulation,

• Riverbank renaturation,

• Reconnection of old side branches of the Danube river.

Besides low water regulation, one major goal of the project is the stabilisation of the riverbed. The progressive

riverbed erosion of the last few decades shall be reduced by means of granulometric riverbed stabilisation. It is

planned to add coarse gravel with a grain diameter of approximately 40 up to 70 mm, which is coarser than most of the Danube’s natural bed load in the project area, but finer than the maximum natural grain size.

The major project goal in terms of inland navigation is to secure adequate fairway conditions at low water

levels. This will be accomplished by means of low water regulation measures such as groynes and training

walls. The distance between groynes, their heights and shapes have been optimised in terms of ecological,


nautical and material-efficient aspects in order to minimise the deposition of sediments in groyne fields and

the formation of scours near the head of a groyne.

The concrete measures for the improvement of navigation foresee:

• Optimization of existing low water regulation to increase its effectiveness, to reduce sedimentation in

groyne fields and to reduce maintenance efforts.

• Dredging and defined reintroduction of material leading to a sediment balance.

• Relocation of certain sections of the existing fairway in order to make use of deeper zones for

navigation purposes. This measure also reduces the requirement for dredging.

• Granulometric riverbed improvement. The reduced transport of bed load also reduces the need for

maintenance dredging.

The realisation of these innovative measures has to be accompanied by a continuous monitoring programme.

As a concrete and already realized example for a successful river engineering adaptation measure via donau

has implemented the so-called "Pilot Project Witzelsdorf" in the years 2007 up to 2009. With this project,

which is part of the "Integrated River Engineering Project on the Danube to the East of Vienna", via donau has optimised the existing groyne field from a nautical, ecological and material-efficient point of view. For the

first time on the Austrian Danube an innovative inclined groyne type, facing downstream, was implemented. In addition, an existing training wall was lowered to be effective only in low water conditions. Furthermore,

the riverbank was renaturated by a complete or partial removal of the old stone protection (rip-rap). The

following figure gives an overview on the implemented measures within this pilot project.

Figure 3.7: Measures within the Pilot Project Witzelsdorf. Source: via donau.

The adaptation of river engineering elements such as groynes and training walls was necessary because of the

continuous erosion tendencies of the riverbed in this section. Due to riverbed degradation the original groyne

was much higher than necessary for effective low water regulation. In this sense the measure can be seen as a good example how to adapt river engineering elements to a changing situation. The following figure displays

the situation before and after the implementation of the adaptation measure.


6. Conclusions

Modern waterway management has to take the potential impact of climate change into consideration.

Waterway management authorities are committed to continuously improve their performances in order to ensure a well-maintained waterway infrastructure in accordance with the internationally agreed fairway

parameters.

As climate change is neither a new phenomenon nor a discontinuous function, waterway management

authorities shall continuously monitor water discharge patterns on the time axis and accordingly adapt their waterway management related activities in case of altered conditions. As rivers are complex and living systems,

waterway management authorities must continuously adapt to a changing framework, be it climate change or e.g. hydromorphological alterations as erosion processes of the riverbed. Having this in mind, the principal

philosophy of modern waterway management shall be based on a continuous improvement process (CIP) of

all waterway management related activities. This philosophy will increase the understanding of the different functions of the river and the interactions between the basic system elements and lead to a truly integrative

waterway management system which will succeed in balancing the needs of inland waterway transport infrastructure and the natural or ecological functions of the rivers.

Concluding, waterway administrations can and shall prepare dedicated climate change adaptation strategies for

a short-, medium and long-term perspective. Whereas adaptation strategies for the short-term perspective can

be implemented immediately in reaction to changing water discharge patterns, medium and long-term strategies need some time to be implemented. Such medium and long-term strategies should include different

sets of measures in order to provide adequate responses to different climate change scenarios.

• Short-term adaptation measures mainly address continuous waterway maintenance activities resp. the

maintenance strategy: In case of changing water discharge patterns (e.g. altered seasonality of low water periods) the fairway maintenance cycle (surveying, dredging, provision of information) shall be

accordingly adapted on the time axis. This includes an optimal timing of the necessary dredging works

during the year which takes into account changing temporal distributions of the river's water discharge. Improved utilisation of the fairway can be achieved by provision and usage of up-to-date

comprehensive information on the fairway conditions as well as implementation of concepts like the fairway-in-the-fairway.

• One general adaptation measure for waterway administrations should be the continuous and differentiated monitoring and analysis of the development of the river’s water discharge regime. The

currently used statistical water level reference indicators (LNWL – Low Navigable Water Level, MWL – Mean Water Level, HNWL – Highest Navigable Water Level) just represent statistical values based

on a long-term (30 years) time series. In order to better evaluate and recognise potential climate

change effects, waterway administrations shall develop additional indicators for alterations in the water discharge regime. Such indicators could include long-term seasonal analysis of the water

discharge regime as well as a dynamic analysis of low water conditions: the lowest water levels within a series of consecutive days (e.g. 3, 5, 7, 10, 21 days).

• Medium and long-term measures include structural modifications of river engineering measures as an adequate response to larger climatic changes. The adaptation of the waterway infrastructure via river

engineering measures (e.g. groynes) should be undertaken on the basis of a continuous monitoring of

the effectiveness of these elements, whereby the monitoring intervals have to be adjusted to the changes in the discharge regime and river morphology (quicker becoming changes require shorter

monitoring intervals).


For the Austrian Danube a future decrease of maintenance works by 40% compared to the current situation is

expected in the future. This estimation is based on the assumption that the water regime remains in the same

bandwidth as the prevailing one, the river engineering project east of Vienna is implemented and improved usage of ICT is taking place. In the case of a significant future change of the Danube´s water regime the

necessary maintenance activities might increase, especially in the case of increased severe flood events. This holds for other European waterways, too. In the case of prolonged low water periods no additional

maintenance works are to be expected, as the dredging works shall be done only once per shallow section,

assuming an optimal timing of the dredging works – which shall take place ideally before the beginning of the low-water period. In the case of a significant reduction of e.g the long-term statistical Low Navigable Water

Level (LNWL) the current navigation parameters (e.g. 2.5 metres fairway depth at LNWL) can only be maintained with the help of additional structural river engineering measures. Such measures are not part of the

daily maintenance works, but have to be planned, evaluated and executed in the framework of dedicated

infrastructure project.s, considering local framework conditions.

Considering the living nature of a river, the interactions between its different stakeholders, political developments and interests, increasing environmental requirements as well as the fact that in the coming

decades planned and acknowledged major infrastructure projects (e.g. TEN-T projects) are very likely to be

implemented, improving the navigation conditions significantly, it is not possible to give an exact, reliable estimate of to which extend and where infrastructure measures have to be taken and what the associated costs

will be.

Implementation of the measures presented will improve the navigation conditions already today. The inland

waterway transport sector will benefit from these measures immediately, not only in an uncertain future.


References

URLs have been verified on April 14th, 2011.

1. BMVBS (2009): KLIWAS - Impacts of Climate Change on Waterways and Navigation in Germany.

Conference Proceedings of the 1st Status Conference. 168 pp. http://www.bmvbs.de/cae/servlet/contentblob/60480/publicationFile/29918/kliwas-

conference.pdf

2. Hahne, L. & B. Söhngen (2010): KLIWAS Project 4.04 - Minimum width of fairways for safe and

easy navigation. http://www.kliwas.de/cln_005/nn_608278/KLIWAS/EN/03__ResearchTasks/04__vh4/04__404/

404__node.html?__nnn=true

3. RMD Wasserstraßen GmbH (2004a): Bundeswasserstraße Donau – Donauausbau Straubing –

Vilshofen Raumordnungsverfahren: Variante A: Weiter optimierter Ist-Zustand, Variante C: Flussregelnde Maßnahmen mit einer Staustufe in Aicha. Erläuterungsbericht.

4. RMD Wasserstraßen GmbH (2004b): Donauausbau Straubing – Vilshofen Raumordnungsverfahren:

Zusammenfassung der Raumordnungsunterlagen.

5. Söhngen, B., Kellermann, J. & A. Kampker (2001): Zusammenfassung der Ergebnisse der

verkehrswasserbaulichen Untersuchungen Februar 2001. Gutachten. Anlage 19. In WSD Süd (2001): Donauausbau Straubing – Vilshofen. Vertiefte Untersuchung. Schlussbericht.

6. WSD Süd (2001): Donauausbau Straubing – Vilshofen. Vertiefte Untersuchung. Schlussbericht.

7. WSV (2011): Fahrrinnentiefen-Rhein. Figure from www.elwis.de (visited on 20.04.2011).

8. Wurms, S. & P.M. Schröder (2010): KLIWAS Project 4.03 - Options for the regulation and

adaptation of hydraulic engineering measures to climate induced changes of the discharge regime. http://www.kliwas.de/cln_005/nn_608266/KLIWAS/EN/03__ResearchTasks/04__vh4/03__403/

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9. ZENAR – Zentrum für Naturgefahren und Risikomanagement (2003): Plattform Hochwasser

Ereignisdokumentation Hochwasser August 2002. Editorial: Helmut Habersack, Andrea Moser.

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