UNDP/GEF DANUBE REGIONAL PROJECT
"STRENGTHENING THE IMPLEMENTATION CAPACITIES FOR NUTRIENT REDUCTION AND
TRANSBOUNDARY COOPERATION IN THE DANUBE RIVER BASIN"
ACTIVITY 1.1.2 "ADAPTING AND IMPLEMENTING COMMON APPROACHES AND
METHODOLOGIES FOR STRESS AND IMPACT ANALYSIS WITH PARTICULAR ATTENTION
TO HYDROMORPHOLOGICAL CONDITIONS"
FINAL REPORT
Univ. Prof. Dr. Otto Moog
DI Dr. Ilse Stubauer
at
BOKU University of Natural Resources and Applied Life Sciences
A-1180 Vienna, Austria
December, 2003
UNDP/GEF DANUBE REGIONAL PROJECT
"STRENGTHENING THE IMPLEMENTATION CAPACITIES FOR NUTRIENT REDUCTION AND TRANSBOUNDARY COOPERATION IN
THE DANUBE RIVER BASIN"
Table of Contents
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UNDP/GEF DANUBE REGIONAL PROJECT
ACTIVITY 1.1.2 - ADAPTING AND IMPLEMENTING COMMON
APPROACHES AND METHODOLOGIES FOR STRESS AND
IMPACT ANALYSIS WITH PARTICULAR ATTENTION TO
HYDROMORPHOLOGICAL CONDITIONS
UNDP/GEF DANUBE REGIONAL PROJECT:
-4-
ACTIVITY 1.1.2. ADAPTING AND IMPLEMENTING COMMON APPROACHES AND METHODOLOGIES FOR STRESS AND IMPACT ANALYSIS
Common Approaches and Methodologies for Stress and Impact
Analysis with particular Attention to Hydromorphological
Conditions
Methodological Approach (Criteria for significant Impact)
OTTO MOOG & ILSE STUBAUER
1.
INTRODUCTION
Paragraph 1.4 in Annex II of the Water Framework Directive (WFD) requires that
Member States shal col ect and maintain information on the type and magnitude of
significant anthropogenic pressures to which surface water bodies in each River
Basin District are liable to be subject. In particular, attention should be given to
pressures from point and diffuse sources, water abstraction, flow regulation,
hydromorphological alterations and land use. Member States shal carry out an
assessment of the susceptibility of the surface water bodies to the pressures
identified. Member States shal use the information col ected, and any other relevant
information including existing environmental monitoring data, to carry out an
assessment of the likelihood that surface water bodies within the River Basin District
wil fail to meet the environmental quality objectives set for the bodies under Article 4.
A summary of the key stages includes:
1. identifying driving forces and pressures,
2. identifying the significant pressures,
3. assessing the impacts, and
4. evaluating the likelihood of failing to meet the objectives.
2.
AIMS OF THIS REPORT
The major goal of this part of the project (Project Document Activity 1.1.2) is to adapt
and implement common approaches and methodologies for stress and impact
analysis with particular attention to water abstraction, flow regulation, and
morphological alterations, herein in summary cal ed hydromorphological
pressures, in the DRB. To achieve this goal three requests for information have
been distributed to each of the national consultants in the Danube countries. The
questionnaires aimed at compiling available information on hydromorphological
pressures and impacts and the definition of criteria for significant pressures.
In the first phase of the UNDP/GEF Danube Regional Project the activities are limited
to the Danube River itself. The Danube River is divided into sections of different
typological characteristics (Project Document Activity 1.1.6 - Typology of Surface
Waters and Definition of Reference Conditions for the Danube River). This
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
classification may serve as a framework for al ocating the water bodies as described
in the WFD.
With respect to the term water body the C.I.S guidance paper REFCOND states:
Where different reference conditions apply within a river, stream or canal, it must be
sub-divided into separate water bodies. Furthermore, where there are significant
differences in status in different parts of a river, stream or canal, it must be sub-
divided into separate water bodies to achieve the desired environmental outcome in
the most cost-effective way.
The implementation of activity 1.1.2 should comprise two steps.
Step 1: Development of the methodological approach (overview on driving
forces and according pressures, development of criteria for significant
impacts of a pressure) (see the fol owing chapters).
Step 2: Overview of stress and impacts caused by changes of
hydromorphological conditions in the Danube River (see chapter 9).
For a common understanding of the terms the Impress guidance paper (C.I.S) has
adopted the widely used DPSIR (Driver, Pressure, State, Impact, Response)
analytical framework with the fol owing definitions. Within the scope of the study a
focus is given on only three criteria: drivers (driving forces), pressures and impacts
(Table 1).
Table 1: Part of the DPSIR framework as used in the pressures and impacts analysis.
Term
Definition
Driver
An anthropogenic activity that may have an environmental effect (e.g.
agriculture, industry)
Pressure
The direct effect of the driver (for example, an effect that causes a change in
flow or a change in the water chemistry)
Impact
The environmental effect of the pressure (e.g. fish kil ed, ecosystem modified)
3.
DEVELOPMENT OF METHODOLOGICAL APPROACH (CRITERIA FOR
SIGNIFICANT IMPACT ANALYSIS)
The output of step 1 is the report at hand on "Common approaches and
methodologies for stress and impact analysis with particular attention to
hydromorphological conditions - Methodological approach (criteria for significant
impact)". The according activities of the international and national consultants
fol owed the given scheme:
Part A: Developing/completing a list of drivers that may cause important
hydromorphological pressures that change the ecological conditions in the
Danube River stretch of the according country.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Part B: Developing/completing a list of pressures induced by each of the drivers
that may cause important impacts on the biotic conditions in the Danube River
stretch of the according country. This list can be used as a national checklist to
inventory the relevant pressures in the Danube River. The checklist may be
helpful/straightforward to note al pressures without concern for their
significance. Final y emphasis wil be put on a transnational agreement of the
proposed pressures in the Danube countries.
Part C: Developing/discussing a system to assess if a pressure has a significant
impact and the water body is at risk to fail the good ecological status.
The questionnaires for part A and part B have been sent to the national consultants
on August 22nd, 2003. The deadline to return the answered questionnaires was
September 4th, 2003. Questionnaire C was sent on August 25th, return deadline has
been specified as September 11th. The questionnaires A, B, and C are attached to
this report in Annex 1. Table 2 gives an overview on the persons who responded to
the questionnaires.
Table 2: Persons who provided the answers to the questionnaires on drivers
Country
Person 1
Institution
Person 2
Institution
Germany
Sebastian Birk
University Duisburg-
Essen
Franz Schöl
BFG Koblenz
Ministry for
BOKU - University of
Austria
Birgit Vogel
Agriculture, Forestry,
Natural Resources
Environment and
Otto Moog
and Applied Life
Water Management
Sciences
Slovakia
Jarmila Makovinska Water Research
Institute
Országos Vízügyi
Országos Vízügyi
Hungary
László Perger
F igazgatóság /
F igazgatóság /
National Water
Szilvia Dávid
National Water
Authority
Authority
Croatia
Marija Jokic
Croatian Waters
Ministry for
Serbia-
Protection of Natural
Montenegro
Jovanka Ignjatovic
Resources and
Momir Paunovic
Institute for Biological
Environment of the
Research
Republic of Serbia
National
Romania
Graziel a Jula
Administration "Apele
Romane"
State
State
Moldova
Liudmila Cunician
Hydrometerological
Liudmila
Hydrometerological
Service
Serenco
Service
Bosnia-
JP za "Vodno
JP za "Vodno
Herzegovina
Bozo Knezevic
podrucje slivova
Naida Andelic
podrucje slivova rijeke
rijeke Save"
Save"
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 3: Date of distribution and reply of questionnaires
Questionnaire sent
Reply obtained
Country
Name
Part A & B Part C
Part A & B Part C
Germany
Sebastian Birk/Franz
22.8.03
25.8.03
27.10.03
27.10.03
Schöl
Austria
Birgit Vogel/Otto Moog
22.8.03
25.8.03
27.10.03
27.10.03
Czech Republic
Ilja Bernardova
22.8.03
25.8.03
not fil ed in because no
direct access to Danube
Slovakia
Jarmila Makovinska
22.8.03
25.8.03
12.10.03
20.10.03
Hungary
Lazlo Perger/ Szilvia
22.8.03
25.8.03
3.11.03
3.11.03
Dávid
Slovenia
Natasa Vodopivec
22.8.03
25.8.03
not fil ed in because no
direct access to Danube
Croatia
Marija Jokic
22.8.03
25.8.03
27.10.03
-
Bosnia-
Bozo Knezevic / Naida
22.8.03
25.8.03
31.10.03
no direct
Herzegovina
Andjelic
access to
Danube
Serbia-
Momir Paunovic/Jovanka
22.8.03
25.8.03
30.9.03
30.9.03
Montenegro
Ignjatovic
Bulgaria
George Mungov
22.8.03
25.8.03
-
-
Romania
Graziel a Jula
22.8.03
25.8.03
16.9.03
19.9.03
Moldova
Liudmila Cunician/
22.8.03
25.8.03
29.8.03
10.10.03
Liudmila Serenco
4.
BENEFITS FROM THIS REPORT
The report wil yield a first overview of the kind and relevance of drivers and
pressures in the entire Danube River focusing on the main river channel. The
provided methodology of assessing the impacts of specific pressures may be a basis
of establishing a decision support system, which serves as a methodological
background for a more detailed pressures and impact analysis in the Danube River
as wel as in other Danube tributaries. It further wil help to identify possible gaps of
data availability. On the basis of this information national research projects can be
tailored to fil the remaining gaps. As medium term ultimate object this study serves
as important source of information for step 2, the overview of stress and impacts
caused by changes of hydromorphological conditions in the Danube River.
Besides the pressures & impacts topics the criteria provided in the tables of
questionnaire C may serve as a helpful tool within the discussion on heavily modified
water bodies.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
5.
EVALUATION OF PART A - DRIVING FORCES
The aim of part A was to develop or complete a list of drivers that may cause
important hydromorphological pressures that change the ecological conditions in the
Danube River. This list should serve as a basis for estimating driver specific
pressures.
Table 4 summarises the current status of identifying drivers in the Danube River
countries. Three countries have already started with the process of identifying drivers
(Germany, Austria, and Hungary). In Slovakia and Romania the process is under
development. Croatia, Serbia-Montenegro, Bosnia-Herzegovina and Moldova have
not started with identifying drivers.
Table 4: Current status of identification process for drivers
Country
process
process under
deadline
process not
started
development
started
Germany (D)
x
Austria (A)
x
Slovakia (SK)
x
2004
Hungary (H)
x
Croatia (HR)
X
Serbia-
X
Montenegro (YU)
Romania (RO)
x
Moldova (MD)
X
Bosnia-
X
Herzegovina (BA)
The next question asks for availability of information about driving forces on water
bodies in the Danube countries that can be used in the analysis of pressures and
impacts required by the WFD. The national experts should indicate the "type of
driver" and if available - the source of information (references, reports, position
papers etc.). The outcome of these answered questions provides quite useful results
that are summarised in Table 5.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 5: List of sources for drivers mentioned by national experts
Country
Type of Driver
Source of Information
navigation
BANNING (1998): Auswirkungen des
flood defence
Germany
Aufstaus größerer Flüsse auf das
Makrozoobenthos - dargestel t am Beispiel
hydropower generation
der Donau. Essen (Westarp-Wiss.).
navigation
Danube waterway map (http://www.via-
donau.org)
flood defence
hydropower generation
Information about Danube hydropower
Austria
stations (http://www.verbund.at)
gravel extraction
river bed survey
(http://www.wsd.bmv.gv.at)
(http://www.donautechnik.at)
navigation
WRI, Danube River Authority, SK (GIS)
hydropower generation
Danube River Authority, Slovak Electricity
Company, Water Management Building
Slovakia
Company SK (electronical data, maps,
reports)
flood protection
WRI, Danube River Authority, SK
navigation
hydropower generation
Hungary
flood defence
CD with ArcView shape available
outdoor recreation
gravel extraction
Croatia
Serbia-Montenegro
flood defence
Water Cadastre of Romania-1992-
section Cadastre of Hydraulic Works hard
copy
Hydrological Monograph-hard copy
Romania
navigation
hydropower generation
Water Cadastre of Romania-1992 hard
water abstraction
copy
fisheries
Moldova
To gain an overview on the driving forces in the Danube countries a list of the known
most important drivers that may change the hydromorphological conditions in the
Danube River was provided by the international consultants. The national consultants
were encouraged to:
1. indicate drivers relevant for the Danube section in their country
2. indicate major driving forces in the Danube section
-10-
MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
3. (if possible) perform a ranking of the major driving forces in the Danube section.
As a final result a list of driving forces relevant for sections of the Danube River in the
countries, ranked due to their relevance for each national Danube section was
expected.
The fol owing tables provide a listing of the most important drivers that may change
the hydromorphological conditions in the Danube River. Although most of the
Danube countries are currently identifying the drivers or have not yet started
respectively, al questionnaires contained responses to the types of drivers.
Consultants from eight countries could rank the drivers according to their relevance
(Table 6).
Table 6: Types of drivers (ranking: 1,2,3; if number not bold, no major driver; X: major driver, but not
ranked; y: relevant, (y): only of local relevance)
Country
D
A
SK
H
HR
YU
RO
MD
BA
flood defence
1
1
2
1
y
2
2
2
1
navigation
1
2
1
y
4
3
4
y
hydropower generation
1
1
1
y*
1
1
1
2
water abstraction
y
3
y
3
y
gravel extraction
3
3
2
3
y
fisheries
(y)
removal of plants/animals
(y)
inshore habitat
management
outdoor recreation
y
4
y
other drivers
inter basin transfer
X
water intake
* not relevant, but from upstream measurable
Hydropower generation is seen as the most important driving force, fol owed by flood
defence measures and navigation as the tertiary (Table 6). Fisheries, removal of
plants/animals and inshore habitat management are not seen as relevant drivers with
a remarkable pressure on the Danube environment. Two more drivers have been
added by Hungary, the inter basin transfer and the water intake. Al together eight
drivers have been regarded as anthropogenic activities that may have an
environmental effect on the Danube River. The relevant driving forces are
summarised in order of their importance in Table 7.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 7: List of relevant drivers that cause a remarkable pressure on the Danube River environment
Drivers relevant for the Danube
hydropower generation
flood defence
navigation
gravel extraction
water abstraction
outdoor recreation
fisheries
inter basin transfer
water intake
6.
EVALUATION OF PART B - HYDROMORPHOLOGICAL PRESSURES
The questionnaire starts with the query if the process of identification concerning
hydromorphological pressures for the Danube River has started. If this process has
started the national consultants were asked to indicate what kind of information about
pressures on water bodies wil be available. A focus should be given on information
that can be used in the analysis of pressures and impacts required by the WFD, and
- if available - the source of information (references, reports, position papers etc.).
Table 8 summarises the current status of identifying pressures in the Danube River
countries. Three countries have already started with the process of identifying
pressures (Germany, Austria, and Hungary). Romania is under development.
Slovakia, Croatia, Serbia-Montenegro, Bosnia-Herzegovina and Moldova have not
started with the process of identifying pressures.
Table 8: Current status of identification process for pressures
Country
process
process under
deadline
process not
started
development
started
Germany
x
Austria
x
Slovakia
x
Hungary
x
Croatia
x
Serbia-Montenegro
x
Romania
x
Moldova
x
Bosnia-Herzegovina
x
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Al suggested pressures of the driver "flood defence" (Table 9) have been confirmed
as impacts induced by flood protection measures. No other pressures have been
appended. Alteration of the river course and channel form/profile is regarded as the
most important pressure (six votings out of eight; two times ranked as major
pressure). The categories "flood defence dams, set-back embankments, dykes" (six
votings out of eight; one time ranked as major pressure), "alteration of the
hydrological/hydraulic characteristics" (six votings out of eight) and "alteration of the
bank vegetation and banktop land use" (five votings out of eight) fol owed as major
pressures.
Table 9: Pressures related to driver "flood defence", most important pressures are ranked with
numbers (not for al countries provided); major pressure indicated with X if no ranking
possible, minor relevance indicated with y
Pressures of the driver
D
A
SK
H
HR
YU
RO
MD
BA
"flood defence"
Alteration of the river course and X
1
X
X
1
X
channel form/profile (e.g.
straightening, curvature,
channel ing, diversions)
Disruptions of the vertical
3
X
Y
3
connectivity (e.g. siltation,
colmation, embeddedness,
plastering, concrete bottom)
Disruption of the longitudinal
3
X
4
y
X
connectivity (e.g. weirs, ramps)
n
Alteration/modification of
X
1
y
X
o
t
X
X
y
y
p
morphological in-channel
o
s
features/habitats; bank fixation,
s
i
reinforcements, re-insectioning,
b
l
e
embankment, groynes
t
o
Disruptions of lateral
2
X
X
a
n
2
y
y
connectivity (e.g. detaching of
s
w
side arms, tributaries)
e
r
Alteration of the bank vegetation
1
X
X
2
y
and banktop land use
(floodplains)
Flood defence dams, set-back
2
X
X
1
X
X
embankments, dykes
Alteration of the
X
Y
X
X
Y
4
X
X
hydrological/hydraulic
characteristics (flow
regime/sediment transport)
Other pressures
Compared to the effects of flood defence the navigation impacts have been classified
as less important in a countrywide average (Table 10). Anyhow al pressures
proposed have been confirmed. No additional pressures driven by navigation have
been suggested. In most countries the "alteration of the hydrological/hydraulic
characteristics" (six votings out of eight) has been voted as important pressure, but
never as major one. The ranking is fol owed by "alteration of the river course and
-13-
MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
channel form/profile", "Disruptions of lateral connectivity" and "alteration of
morphological features/habitats" with each five votings out of eight.
Table 10: Pressures related to driver "navigation", most important pressures are ranked with numbers
(not for al countries provided); major pressure indicated with X if no ranking possible, minor
relevance indicated with y
Pressures of driver
D
A
SK
H
HR
YU
RO
MD
BA
"navigation"
Alteration of the river course
X
1
y
X
3
X
(thalweg) and channel
form/profile
Alteration of morphological
X
X
X
X
3
y
features/habitats (e.g.
embankments, bank
reinforcement, groynes, deep-
cutting, dredging, shipyards and
harbours)
Disruptions of longitudinal
X
Y
y
3
connectivity
n
o
Disruptions of lateral
X
2
X
X
t
p
4
connectivity, e.g. detaching
o
s
sidearms, wetlands etc.
s
i
b
l
Disruptions of the vertical
y
Y
X
e
4
t
connectivity
o
a
Alteration of the
X
2
X
X
n
s
2
X
hydrological/hydraulic
w
e
characteristics (flow
r
regime/sediment transport)
Maintenance of the shipping
y
1
y
y
y
3
X
channel (e.g. dredging)
Ship locks
y
Y
y
y
y
4
Harbours
y
Y
y
y
y
2
y
y
Mechanic damage of aquatic
y
Y
3
flora caused by passage of
ships, e.g. effect of vessel-
induced waves
Other pressures
With respect to hydropower use al pressures proposed have been confirmed (Table
11). No additional pressures driven by hydropower have been suggested. With seven
quotings out of a total of eight countries the "disruptions of the longitudinal
connectivity" is seen as the most important pressure of this category. The second
category of high importance is the "alteration of the hydraulic characteristics" (six
votings out of eight). This category has been ranked as the major pressure in three
countries (Germany, Austria, Romania). Al other categories have been indicated with
lesser importance.
"Alteration of the river course and channel form", "disruptions of lateral connectivity",
and "alteration of the hydrological (discharge) regime" with each four votings out of
eight are regarded as important pressures in 50 percent of the countries.
-14-
MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 11: Pressures related to driver "hydropower use", most important pressures are ranked with
numbers (not for al countries provided); major pressure indicated with X if no ranking
possible, minor relevance indicated with y
Pressures of driver
D
A
SK
H
HR
YU
RO
MD
BA
"hydropower use"
Disruptions of the longitudinal
2
1
X
y
X
1
X
X
connectivity (barrages, weirs,
dams)
Ship locks (water gates, sluices)
3
Y
y
1
Disruptions of lateral
1
X
y
2
X
connectivity (embankments,
dams)
Alteration of the river course
2
Y
X
X
1
(thalweg) and channel form,
n
o
diversions
t
p
o
Alteration of morphological
2
1
Y
s
1
s
features/habitats as described
i
b
l
for flood defence measures
e
t
o
Disruptions of the vertical
2
Y
a
X
1
connectivity (silting, colmation)
n
s
w
Alteration of the hydrological
Y
X
y
e
X
2
X
r
(discharge) regime
Alteration of the hydraulic
1
1
X
1
X
characteristics (current,
sediment load)
Water abstraction, diversions
2
(residual flow)
Hydro-peaking (flushing;
Y
y
2
X
intermittent power generation)
Other pressures
X*
*: Pressure of hydropower use above Hungary
Al proposed pressures with respect to the driver "water abstraction" have been
confirmed by the national consultants (Table 12). No additional pressures driven by
water abstraction have been suggested. The maximum number of voting were two
out of eight countries, no ranking was performed. Only the first five pressure
categories have been seen as possibly important.
Table 12: Pressures related to driver "water abstraction", most important pressures are ranked with
numbers (not for al countries provided); major pressure indicated with X if no ranking
possible, minor relevance indicated with y
Pressures of driver "water
D
A
SK
H
HR
YU
RO
MD
BA
abstraction"
r
p
r
Abstraction for hydropower use e n
l
o n
e n
e o
3
s o
l
e o
y
X
t
t
t
(see above)
Abstraction for agriculture or
X
y
floodplain irrigation
Abstraction for drinking water
X
y
X
supply
Abstraction for industry
X
X
y
-15-
MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Pressures of driver "water
D
A
SK
H
HR
YU
RO
MD
BA
abstraction"
Abstraction for cooling water
X
facilities
Abstraction for fish farming
Abstraction for navigation
y
(harbours; supplying canals)
Alteration of the river course
(thalweg) and channel form
Alteration of morphological
features/habitats disruptions of
longitudinal connectivity
Disruptions of lateral
connectivity
Disruptions of the vertical
connectivity
Alteration of the
hydrological/hydraulic
characteristics (flow regime,
sediment load)
Other pressures
Gravel extraction has been regarded as pressure, but of minor importance (Table
13). Nevertheless four countries out of eight would expect modifications of river
channel, in-channel habitats and banks, three countries noticed the alteration of
amount and composition of the bed sediments as noticeable pressure. No new
category of pressure induced by gravel extraction was added.
Table 13: Pressures related to driver "gravel extraction", most important pressures are ranked with
numbers (not for al countries provided); major pressure indicated with X if no ranking
possible, minor relevance indicated with y
Pressures of driver "gravel
D
A
SK
H
HR
YU
RO
MD
BA
extraction"
Alteration of amount and
X
X
X
composition of the bed
n
n
o
n
sediments
o
t
t
o
a
r
p
n o
t
r
Increased turbidity (suspended
e
l
s
e
e
s
w s
l
e
solids)
v
e i
a
b
r l
v
e
a
Modifications of river channel,
n
t
X
X
X
t
X
n
t
y
o
in-channel habitats and banks
Other pressures
Pressures induced by the driver "fisheries" were not fil ed in by any country. The
same with pressures of the drivers 4removal (harvesting) of animals/plants",
pressures of the driver "inshore habitat management" and "fine sediment deposition
management", respectively.
Pressures induced by "outdoor recreation" were only mentioned as minor pressures
by Austria and Hungary (Table 14).
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 14: Pressures related to driver "outdoor recreation", most important pressures are ranked with
numbers (not for al countries provided); major pressure indicated with X if no ranking
possible, minor relevance indicated with y
Pressures of driver
D
A
SK
H
HR
YU
RO
MD
BA
"outdoor recreation"
Modifications of river channel,
y
in-channel habitats and banks
for recreation purposes as there
are fishing (facilities; houses;
bank alterations), recreational
navigation (e.g. harbours),
boating, rafting, water ski ng...
Other pressures
7.
EVALUATION OF PART C - SIGNIFICANT PRESSURES AND IMPACTS
The third questionnaire (part C) aimed to provide an overview on methodologies and
tools 1) that are currently used to assess the potential impact of human activity on
water bodies, and 2) that are planned in the future. A third important focus of
questionnaire C is to discuss an approach - proposed by the international consultants
- to assess if a pressure has a significant impact and the water body is at risk to fail
the good ecological status.
The answers to the first block of questions give an overview which methodologies
and tools are currently used to assess the potential impact of human activity on water
bodies (Table 15). With respect to morphological degradation Germany and Austria
use eco-morphological classifications that are summarised as ,,strukturökologische
Methoden". The methods used in Hungary have not been specified in detail.
Germany, Austria, Slovakia and Hungary report on monitoring of the channel
geometry that gives evidence to alteration of bed sediments (amount/structure).
Although al Danubian countries probably monitor the channel geometry due to the
maintenance of the navigation channel this activity cannot be counted as a method to
document structural deficits. Austria, Slovakia, Hungary, Serbia-Montenegro and
Romania report on new methodologies and/or tools planned in the future to assess
the potential impact of human activity (Table 16).
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 15: Answers to question ,,Which methodologies and tools do you currently use to assess the
potential impact of human activity on water bodies (focus: only hydromorphology)?"
Country Type of pressure
Methodologies and tools that are currently
used to diagnose the potential impact of
different anthropogenically induced
hydromorphological pressures
D
morphological degradation
LAWA Übersichtsverfahren zur
Strukturgütekartierung von Fliessgewässern
A
morphological degradation
eco-morphological classification systems for al
federal states, based on ,,Ökomorphologische
Gewässerbewertung" (Werth 1987) and
,,Strukturökologische Methode zur
Bestandsaufnahme und Bewertung von
Fließgewässern" (Spiegler 1989)
hydropower generation
hydrological monitoring
SK
hydrological regime
hydrological monitoring (discharges, water levels,
sediment transport)
changes in river bed
monitoring of the River channel geometry
morphology
alternation of morphological
no tool currently used
in-channel features, bank
reinforcement
H
alteration of amount and
composition of the bed
sediments
analysis of human impacts by means of different
modification of river channel,
data (name of method not specified in
in-channel habitats and
questionnaire)
banks for recreation
purposes on rivers
modification of river channel,
in-channel habitats and
banks for recreation
purposes on lakes
intake of waste water,
cooling water etc.
YU
hydropower use
flow regime analyses, deposition overlook,
observation of flora/fauna alternation in relation to
period before the damming
RO
no assessment of potential impact of human
activity on water bodies
MD
barrage
currently no method available
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 16: Answers to question ,,Do you have any new methodologies/tools planned in the future to
assess the potential impact of human activity, e.g. research & development projects or new
mathematical models?"
Country
Methodologies and tools planned in the future to assess the potential
impact of human activity
D
A
research projects;
eco-morphological classification system with common parameters for the whole
country planned for the risk assessment (WFD), based on water bodies
SK
research projects
H
Since the end of the year 2001 Hungary owns the ADCP instrument which
al ows the measurement of suspended sediment and bed load too. Now there
exists five of this instruments in the country, of which three are measuring on
the Danube. The instrument is not calibrated on measurement of the sediment
yet, but it is planned now.
YU
research projects
RO
mathematical model planned
MD
no tools planned
Each country with a direct access to the Danube indicates gaps in knowledge that
wil be needed to fulfil the WFD's requirements. Germany is missing a methodology
for the assessment large rivers. The Austrian representatives state that future
methods should detect al pressures and assess al impacts. The methodologies
should cover the water bodies as typological entity. Besides the hydro-morphological
methodology, Hungary claims for the measurement of some specific synthetic and
non-synthetic pol utants and indicate gaps in their frequency. Serbia-Montenegro
sees the necessity for additional investigations of 1) flow alternation to community
structure, and the 2) influence of flow alternation to the dispersion of invasive
species. The comments from Romania state that there is a lack of information on the
relation between hydromorphology and biological elements. In a second comment
Romania points out the difficulty in assessing river sections that are impaired by
multiple stressors (Table 17).
Table 17: Answers to question ,,Please indicate any gaps in knowledge that wil need to be fil ed to
fulfil the WFD's requirements on the impacts of pressures, such as the effect of morphological
alterations on biological elements."
Country
Gaps in knowledge that will need to be filled to fulfil the WFD's
requirements on the impacts of pressures
D
Methodology for the assessment of large rivers is missing.
A
Methods should detect al pressures and assess al impacts, based on water
bodies.
SK
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Country
Gaps in knowledge that will need to be filled to fulfil the WFD's
requirements on the impacts of pressures
H
The WFD contains the hydromorphological quantity elements to be fulfil ed for
the good ecological status. Concerning these elements there is a gap in the
measurement in Hungary of some specific synthetic and non-synthetic
pol utants and in their frequency. The sampling of the water quality does not
refer to the hydrological measurements because the sampling of the two
elements belongs to two different authorities. Especial y on smal rivers quality
samplings are not frequent enough, there are pol utions that can remain
unknown. (On larger rivers there are samplings two times per month on
appointed places four times).
YU
The relation of many hydrobionts to migration is not properly studied; the
differences between the macrozoobenthos of littoral part of the lakes and bank
region of the potamon, when the substrate type is similar, are often tiny and
hard to measure and express (as it is the case with oligochaete community) - in
that direction, it is hard to express the impact of the alternation of the flow
regime of potamon, especial y in sectors with backwater effect, via biological
elements such as aquatic macroinvertebrates - so, maybe, the additional
investigation of flow alternation to community structure should be performed;
the influence of flow alternation to the dispersion of invasive species is another
important topic that should be seriously discussed.
RO
Not enough information on the relation between hydromorphology and
biological elements available; synergy of different types of pressures on
biological elements sometimes difficult to assess the effect of only one type of
pressure
MD
Methodologies and tools to assess morphological impact are not available.
The next questions assemble the views and details of practice in defining ,,significant"
pressures as the WFD requires that Member States identify ,,significant" human
pressures. Three countries, Germany, Austria, and Romania use an assessment of
significant hydromorphological pressures as a water management tool (Table 18).
More details about the status quo in these countries are given in Table 19.
Table 18: Answers to question ,,Do you use an assessment of `significant' hydromorphological
pressures within water management, perhaps as part of a risk based decision-making
framework?"
Country
yes
no
D
x
A
x
SK
x
H
x
YU
x
RO
x
MD
x
The Austrian national consultants state that Austria is applying an assessment for
,,significant" hydromorphological pressures (pressure criteria). Further, currently a
method for the estimation of impact degree resulting from specific
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
hydromorphological pressures is being developed in Austria. The methodology
fol ows the type-specific approach focusing on different effects of individual pressures
on the ecological status within different river types. The method wil be based on a
scoring system including individual weighting of pressures. Overal , this management
tool aims to enable the classification of pressures and their impact on the ecological
status as wel as the efficient fulfilment of WFD requirements concerning
hydromorphology. For large rivers, especial y the Danube, this new system has not
been tested.
Table 19: Assessment of significant hydromorphological pressures
Country
Type of hydromorphological Assessment of significant
pressure
hydromorphological pressures
morphological degradation
river stretches are classified to have a
significant pressure:
if they are classified with a "structure quality
class" (Gewässerstrukturklasse) of 6 or 7.
stretches where the biota are significantly
impacted due to certain morphological
parameters such as culverting, concrete
regulation of banks and river bottom etc.
longitudinal continuity
river stretches are classified to have a
significant pressure:
D
if the longitudinal continuity is disrupted for
biota (fish and benthic invertebrates) by
upstream and/or downstream barriers.
water abstraction
river stretches are classified to have a
significant pressure:
if less that 2/3 of the MNQ is remaining, when
al water abstractions are regarded together.
if they have no legal residual water
requirement and if significant impacts on the
biota are to be expected.
disruption of the longitudinal
criteria which indicate the significance
river continuity by weirs,
threshold (see Table 20)
barrages etc.
disruption of the lateral river
criteria which indicate the significance
continuity by river engineering- threshold (see Table 20)
connectivity to flood plains
(dykes, agriculture works, fish
farming works)
RO
river engineering banks
criteria which indicate the significance
regulation/consolidation
threshold (see Table 20)
navigation channel
criteria which indicate the significance
threshold (see Table 20)
water abstraction, residual
criteria which indicate the significance
water flow, reservoirs outflow,
threshold (see Table 20)
flow deviation etc.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
The German contribution focuses on three topics: morphological degradation,
longitudinal continuity and water abstraction. The criteria - delivered by the
representatives of the University Duisburg-Essen - are taken from ,,LAWA AO
,Oberirdische Gewässer und Küstengewässer': Kriterien zur Erhebung von
anthropogenen Belastungen und
Beurteilung
ihrer
Auswirkungen
zur
termingerechten und aussagekräftigen Berichterstattung an die EU-Kommission -
Stand 31.03.03, translated".
River stretches are classified to have a significant pressure if they are classified with
a ,,structure quality class" (Gewässerstrukturgüte-Klasse) of 6 or 7 out of a system
with categories between 1 (very good status, reference) and 7 (far from nature).
With respect to ,,longitudinal continuity" German river stretches are classified to have
a significant pressure if the longitudinal continuity is disrupted for biota (fish and
benthic invertebrates) by upstream and/or downstream barriers.
In the case of water abstraction river stretches are classified to have a significant
pressure if less that 2/3 of the average low flow (MNQ) is remaining (al water
abstractions are regarded together). If they have no legal residual water requirement
and if significant impacts on the biota are to be expected.
The national consultant from Romania presents a table for assessing six types of
significant hydromorphological pressures: 1) Disruptions of the longitudinal river
continuity by weirs, barrages, sil s; 2) Disruptions of the lateral river continuity by river
engineering connectivity to flood plains (dykes, agricultural works, fish farming
works etc); 3) River engineering banks regulation/consolidation; 4) Navigation
channel; 5) Water abstraction, water out-takes, flow deviation; 6) Dams discharges,
hydropeaking. Threshold values are given for the likelihood and for the significance
of a pressure to fail the environmental quality goal (Table 20).
Table 20: Assessment of significant hydromorphological pressures used in Romania
Hydromorphologi-
Effects
Parameter
Likelihood
Significance
cal pressure
threshold
threshold
Disruptions of the
Affect the
Height of the
longitudinal river
migration of biota1
structure2 (cm)
< 20
> 50
continuity by weirs,
and the transport
barrages, sil s
of sediments
Disruptions of the
Affect the riverine
Length of
< 30
> 70
lateral river
vegetation
dykes / Length
continuity by river
of water body
engineering
(%)
connectivity to flood
Affect the lateral
Affected
plains (dykes,
connectivity and
surface/
agricultural works,
< 30
> 70
floodplain
floodplain
fish farming works,
vegetation
surface (%)
etc.)
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Hydromorphologi-
Effects
Parameter
Likelihood
Significance
cal pressure
threshold
threshold
River engineering
Affects the river
Length of bank
banks
cross section,
/ Length of
< 30
> 70
regulation/consoli-
substrate structure
water body (%)
dation
and biota
Navigation channel
Affects biota, the
Width of
< 30
> 70
river bed
navigation
channel / width
of river bed(%)
Water abstraction,
Affect biota and
Intake or
< 10
> 50
water out-takes, flow
bed stability
residual flow /
deviation
multiannual
mean flow (%)
Affect biota
Low flow in
> 100
< 50
river bed /
Q
3
95% + 0,1
(m3/s)
Dams discharges
Affects biota (low
Low flow in
> 100
< 50
hydropeaking
flow)
river bed /
Q
3
95% + 0,1
(m3/s)
Affects the flora
The water level
< 50
> 100
and the banks
gradient / hour
stability
(cm)
1: only the migrating biota
2: values are considered for a sequence > 3 sil s / km. For the isolated sil s, the height of
the barrier > 2 m for the heavily modified water bodies is taken into account
3: Q95% - Minimum monthly multiannual discharge with 95% probability (cm/s)
Comments on the guidance for the analysis of pressures and impacts
According to the REFCOND guidance paper there is not too much information
published on the topic of pressures and impacts analysis. Neither the WFD nor the
guidance papers contain sufficient practical help to implement the Directive's
requirements. Nevertheless some countries in the Danube catchment have already
started to work on the process (Table 18).
To keep the process going, a set of proposals how to classify pressures as significant
impacts some tables have been sent by the international consultants to the national
consultants for comments. A part of the tables represents the actual state of a
process under development in Austria and partly in Germany. Other tables provided
the consultants with suggestions that need to be discussed.
The tables are considered as a tool for estimating impacts within a variety of
hydromorphological pressures with special emphasis to identify significant pressures.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
The examples provided cover only those few pressures that have been investigated
in previous studies or that are in the state of discussion.
The procedure is presented in three stages: 1) a descriptive indication of the likely-to-
be relationship of a pressure's impact along a gradient of five steps of status classes,
2) an assessment of the likelihood and 3) an assessment of the significance that
surface water bodies within the River Basin District wil fail to meet the environmental
quality objectives set for water bodies under Article 4 of the WFD.
Due to the lack of information the pressures described are fairly incomplete
compared to the numbers of drivers given in Table 7 (see questionnaire part B). The
tables started with descriptions in five steps (one reference and four steps of
increasing deviation from the reference) to estimate if a water body is not at risk or at
risk to fail the good status as shown in Table 21. The five class system has been
chosen to enable the application of the evaluation tables that are in current use to
pre-classify the ecological status of a site (e.g. Strukturgüte, adapted Saprobic
System), and to be compatible with the ecological status classes of the WFD.
Table 21: Five class system to estimate if a water body is not at risk or at risk to fail the good
ecological status
Code Presumable status
Risk to fail the good status
1
Reference status
Water body surely not at risk
2
Good ecological status
Water body not at risk
3
Moderate ecological status
Water body needing further assessment to
determine risk
4
Poor ecological status
Water body at risk
5
Bad ecological status
Water body clearly at risk
Out of the five classes two threshold ratios/values are used to describe:
1: the likelihood if the water body is at risk to fail the good ecological status, and
2: the significance of the water body failing the good ecological status
The impacts of the fol owing pressures have been described:
1) Disruptions of the lateral river connectivity by river engineering connectivity to
flood plains, sidearms and backwaters
2) Navigation channel
3) Disruptions of the longitudinal river continuity by weirs/barrages
3 a) Height of the in-channel structures
3 b) Composition of channel substrates (minerogenic bed sediments)
3 c) Migration barriers
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
4) River engineering banks
5) Effects of water abstraction (residual water flow)
6) Effects of hydropeaking (incl. sudden flow reduction)
The international consultants strongly emphasised in the questionnaire, that the
proposed system of determining significant pressures by pre-classifying the status of
a site by abiotic criteria is to be seen as a tool for the purpose of this exercise but
does not replace the assessment of the ecological status based on the
investigation of biological quality elements (algae, macrophytes, benthic
invertebrates, and fish). The national consultants were asked to comment on the
proposed criteria.
1) Disruptions of the lateral river connectivity by river engineering
connectivity to flood plains, sidearms and backwaters
The descriptions and threshold criteria for evaluating the possible effects of a
disruption of the lateral connectivity with the floodplain-system (possibilities for
movements of biota and water to and within floodplain water body types [only for
floodplain rivers]).
The estimates are based on suggestions of BEIER et al. (2002), BMLFUW (2003),
CHOVANEC (2003), JÄGER (2002), SCHMUTZ et al. (2001) and observations of the fish
and benthic invertebrate ecology group of the BOKU (Department Hydrobiology,
Fisheries & Aquaculture).
Table 22: Impact 1) Disruptions of the lateral river connectivity by river engineering connectivity to
flood plains, sidearms and backwaters
1
Flood plains correspond total y or nearly total y to undisturbed conditions; minimum
lateral extension should guarantee any type of site-specific natural backwaters
2
At least 50% of the flood plains and/or important site-specific types of backwaters
existing, lateral connectivity in most (at least 50%) cases intact.
3
Floodplain vegetation and lateral connectivity of most backwater types disrupted to
between 50%-75%
4
Floodplain vegetation and lateral connectivity of most backwater types disrupted to
between 75-90%
5
Less than 10% (of formerly existing) floodplains and/or backwaters present.
Decision guidance to pre-classify the likelyhood (border between 2 and 3) or
significance (worse than 3) of the water body failing the good ecological status:
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Threshold ratio to assess the likelihood if
Floodplain vegetation and lateral connectivity of
the water body is at risk to fail the good
most backwater types disrupted to more than
ecological status:
50%*)
Threshold ratio to assess the significance of
Floodplain vegetation and lateral connectivity of
the water body failing the good ecological
most backwater types disrupted to more than
status:
75%*)
*) Currently the decision should be based on expert judgement as precise criteria for
classification need to be developed in the future.
Table 23: Comments of the national consultants to Table 22: Impact 1) Disruptions of the lateral river
connectivity by river engineering connectivity to flood plains, sidearms and backwaters
Country
comments
D
no additional comments
A
The suggested criteria concerning lateral disruption are reasonable for pre-
classifying the likelihood of eventual failure of good ecological status of a water
body. The criteria correspond to the national criteria. Besides the suggested
criteria, national methods can additional y contribute the pre-classification of
this pressure.
Further, we recommend the development of a guidance providing definitions on
lateral connectivity of floodplains and on the applied identification of floodplain
disconnection.
SK
Slovak stretch of the Danube can be pre-classified somewhere between 2 and
4 (floodplain vegetation and lateral connectivity of most backwater types
probably disrupted to more than 50%.
H
Most of the Hungarian rivers bear a disruption of the lateral river connectivity by
river engineering because of the situation of the country which predict the 2-3
groups that wil characterise our rivers. The groups above classify clearly the
water bodies of Europe so we accept this categorisation.
YU
Looks like applicable table not complicated and clear ranking parameters;
required data could be evaluated without extensive analysis of different
information.
RO
see Table 20
MD
agree with statements
With the exception of Germany (no comments to the table) and Romania (Table 20)
al countries agreed with the proposed classification system. The Romanian
threshold value of less than 30% damage to the floodplains is more rigid (Table 20)
than the suggested value of <50%. The values to estimate a significant impact are in
a comparable order of magnitude (70 and 75%).
2) Navigation channel (large rivers)
The descriptions and threshold criteria for evaluating the possible effect of navigation
on the biota refer to the share of the navigation channel with respect to the river's
width. The estimates are based on mere suggestions of the benthic invertebrate
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
ecology group of the BOKU (Department Hydrobiology, Fisheries & Aquaculture),
and expert consultancy. Navigation channel includes navigation channel plus parts of
the river that are maintained or have constructions in combination with the navigation
channel (e.g. deflectors, groynes, and harbours).
It needs to be discussed if in-channel measures outside the navigation channel that
guarantee the functioning of the navigation channel (e.g. groynes) should be included
into the area of the "navigation channel" sensu stricto. In discussing the effective
width of the navigation channel please mind the effects of wash of the waves or of
the ships' propel er on the biota (in regard to width and depth of the channel and the
size, type and frequency of vessels, respectively).
Table 24: Impact 2) Navigation channel (large rivers)
1
No navigation channel
2
Navigation channel covers <33% of the bottom area; no significant effects of wash of
the waves or of the ships` propel ers on the biota
3
Navigation channel covers about 33-66% of the bottom area; possible effects of wash
of the waves or of the ships' propel ers on the biota (in regard to width and depth of the
channel and the size, type and frequency of vessels respectively)
4
Navigation channel covers about 66-100% of the bottom area; possible effects of wash
of the waves or of the ships' propel ers on the biota (in regard to width and depth of the
channel and the size, type and frequency of vessels respectively)
5
Navigation channel covers 66-100% of the bottom area; significant effects of wash of
the waves or of the ships' propel ers on the biota (see above)
Decision guidance to pre-classify the likelyhood (border between 2 and 3) or
significance (worse than 3) of the water body failing the good ecological status:
Threshold value to assess the likelihood if the
Navigation channel covers >33% of the
water body is at risk to fail the good ecological
bottom area
status:
Threshold value to assess the significance of the
Navigation channel covers >66% of the
water body failing the good ecological status:
bottom area
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 25: Comments of the national consultants to Table 24: Impact 2) Navigation channel (large
rivers)
Country
Comments
D
no additional comments
A
So far the chosen criteria are reasonable for application in the Danube main
channel; upcoming assessment experience on this specific issue wil show if
there wil be a demand of criteria modification.
SK
Slovak stretch: navigation channel covers about 33-66% of the bottom area,
but no significant effect of wash of the waves or of the ships´ propel ers on the
biota.
H
We do not make any comments to the tables, for Hungary the groups given
above are entirely acceptable in the water management.
YU
It is good to evaluate the effect of navigation by the width of the route that is
used for navigation. From the other side, we could not see the way of
evaluating the effect of ship propel er induced waves (or ship induced waves -
prow wave) to the biota. It is a significant parameter for sure, but maybe it
should be mentioned that investigation of effects of that kind of pressure should
be performed. The other parameter that could be relevant beside those that are
mentioned in the table is evaluation of ship traffic in relation to relevant sector
by, for example calculation of shipment (cargo) per time unit.
RO
see Table 20
MD
agree with statements
With the exception of Germany (no comments to the table) al countries agreed with
the proposed classification system or provided suggestions in the same order of
magnitude (Romania, Table 20). The consultants from Serbia-Montenegro stated that
an investigation on the effect of ship propel ers induced waves or ship induced waves
- prow wave would be necessary for further assessment.
3) Disruptions of the longitudinal river continuity by weirs/barrages
3a) Criterion: Height of the in-channel structures
An essential criterion for the impact of morphological alterations on the ecological
status of water bodies is the continuity for aquatic communities. This is why it is
essential to identify any artificial obstructing features above a gradient (to be
quantified in cm) and to assess their effect on the continuity of aquatic fauna
(upstream and downstream movement). The descriptions and threshold criteria for
evaluating the possible effects of weirs and barrages refer to the conditions in the
parts of the river channel at, above, and below the in-channel structures. The
estimates are based on suggestions of BMLFUW (2003), CHOVANEC (2003), JÄGER
(2002), LAWA (2002) and observations of the fish and benthic invertebrate ecology
group of the BOKU (Department Hydrobiology, Fisheries & Aquaculture). The table
has been provided for al types of water bodies, in this context only the part for large
rivers should be regarded.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 26: Impact 3a) Disruptions of the longitudinal river continuity by weirs/barrages, Criterion: Height
of the in-channel structures
1
No artificial in-channel structures
2
Artificial in-channel structures that do not affect the migration of biota/sediments.
Description to estimate the significance of the pressure:
in rhithral courses with a maximum free-fal of 10 cm (smal )/30 cm (mid-sized)/70 cm
(large rivers),
in potamal river courses with a maximum free-fal of 10 cm (smal to mid-sized) or
30 cm (large rivers).
The evaluation of the effect of in-channel structures has to include the migration
possibilities during low flows as wel as the technical options for migrations (e.g. start
and landing facilities for jumping fish).
If the height of the artificial in-channel structures exceeds 10/30/70 cm a wel
functioning passage of the biota must be available (e.g. by fish passes, bypasses or
other measures; see 3c).
3
Artificial in-channel structures do affect the migration of biota/sediments.
Description to estimate the significance of the pressure: the height of the artificial in-
channel structures exceeds the limits of a maximum free-fal :
in rhithral rivers of 10 cm (smal ), or 30 cm (mid-sized), or 70 cm (large rivers);
in potamal river courses with a maximum free-fal of 10 cm (smal to mid-sized) or 30
cm (large rivers).
4
Artificial in-channel structures do severely affect the migration of biota/sediments. The
height of the artificial in-channel structures clearly exceeds the migratory power of most
of the biota.
5
Artificial in-channel structures do severely affect the migration of biota.
The height of the artificial in-channel structures clearly exceeds the migratory power of
any biota.
Decision guidance to pre-classify the likelyhood (border between 2 and 3) or
significance (worse than 3) of the water body failing the good ecological status:
Threshold values to assess the likelihood if
Migration not possible for every organism.
the water body is at risk to fail the good
The height of the artificial in-channel structures
ecological status:
exceeds the limits of a maximum free-fal :
in rhithral rivers of 10 cm (smal ), or 30 cm
(mid-sized), or 70 cm (large rivers);
in potamal river courses with a maximum free-
fal of 10 cm (smal to mid-sized) or 30 cm
(large rivers).
Threshold values to assess the significance
No migration possible.
of the water body failing the good ecological
status:
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 27: Comments of the national consultants to Table 26: Impact 3a) Disruptions of the longitudinal
river continuity by weirs/barrages, Criterion: Height of the in-channel structures
Country
comments
D
no comments to the table
A
The disruption of longitudinal river continuity represents a frequent and
therefore important pressure on ecological status. The suggested criteria are
reasonable respecting differences in rhithral and potamal river courses. The
chosen criteria are additional y in line with the Austrian national criteria.
SK
Slovak stretch of the Danube - 5 (no migration possible)
H
The groups given above to characterise the disruptions of the longitudinal river
continuity by weirs/barrages are for Hungary total y acceptable because it wil
make possible the grouping of al the water bodies of the country.
YU
no comments to the table
RO
see Table 20
MD
agree with statements
With the exception of Germany and Serbia-Montenegro (no comments to the table)
and Romania (Table 20) al other countries agreed with the proposed classification
system. The Romanian threshold value to assess the likelihood if the water body is at
risk to fail the good ecological status (height of the artificial in-channel structures
exceeds 20 cm) is more rigid than the proposed value of 30 cm. The Romanian
threshold value to assess the significance is >50 cm, whereas the proposal above
just uses the descriptive criterion ,,No migration possible".
3b) Criterion: composition of channel substrates (minerogenic bed sediments,
reduced flow in the river bed)
The descriptions and threshold criteria for evaluating the possible effect of weirs and
barrages on the composition of bed sediments (e.g. bedrock, boulders, cobbles,
pebbles, gravel, sand, mud, clay) refer to the conditions in the parts of the river
channel at, above, and below the in-channel structures.
The estimates are based on observations of the fish and benthic invertebrate ecology
group of the BOKU (Department Hydrobiology, Fisheries & Aquaculture), the
Austrian system for pre-classifying the ecological status of the AQEM and STAR
projects (http://www.aqem.de, http://www.eu-star.at) and expert consultancy.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 28: Impact 3b) Disruptions of the longitudinal river continuity by weirs/barrages. Criterion:
composition of channel substrates (minerogenic bed sediments, reduced flow in the river bed)
1
No artificial in-channel structures. Composition of channel substrates and features
(bars, islands) correspond to near natural conditions.
2
River channel with natural bed sediments, channel features like side/point/mid-channel
bars and current conditions in at least 70% of the section; the dominant minerogenic
habitats comprise a share of at least 70% of the reference composition (e.g. beginning
of the backwater area).
3
River channels' bed sediments turn to smal er grain sizes compared to the reference
conditions, flow velocities diminuate. Most channel features like side/point/mid-channel
bars under water (impounded). This section can be roughly estimated within the
dammed/impounded river sections as the reach below the beginning of the backwater
area and above the turning point [Wendepegel].
The share of dominant minerogenic habitats of the reference composition is between
<70 and 30%.
4
Sediment conditions and flow velocities in the river channel are remarkably different
from reference conditions (smal er grain diameters, lentic flows). This section can be
roughly estimated within the dammed/impounded river sections the reach below the
turning point [Wendepegel] and above a section as described below (5). The share of
dominant minerogenic habitats of the reference composition is less than 30%.
5
Bed sediments of the river channel are quite remarkably different from natural
conditions, in many cases consisting of untypical fine sediments (mud, pelal), nearly no
current. Mainly restricted to dammed/impounded river sections in front of the weir.
Decision guidance to pre-classify the likelyhood (border between 2 and 3) or
significance (worse than 3) of the water body failing the good ecological status:
Threshold ratio to assess the likelihood if the The share of dominant minerogenic habitats of
water body is at risk to fail the good
the reference composition is between <70 and
ecological status:
30%.
Threshold ratio to assess the significance of
The share of dominant minerogenic habitats is
the water body failing the good ecological
less than 30% of the reference composition
status:
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 29: Comments of the national consultants to Table 28: Impact 3b) Disruptions of the longitudinal
river continuity by weirs/barrages. Criterion: composition of channel substrates (minerogenic
bed sediments, reduced flow in the river bed)
Country
comments
D
no comments to the table
A
The suggested criteria are reasonable for pre-classification.
SK
Slovak stretch of the Danube - between 2-3
H
The criterions made on the grounds of the composition of channel substrates
are without affixing acceptable for Hungary.
YU
The parameter "deposition of untypical fine sediment" that was used for class
No. 5, could be used for classes 3 and 4 also - for example, the deposition of
mud in near-bank habitats (littoral habitats) could be observed in back-waters
even if the particular stream could not be characterised as No. 5 by disruption
of the longitudinal continuity - so, the percentage of fine sediment in the littoral
region (percentage of pelal habitats) could be used for additional parameter in
other classes. From the other side, the parameter is not reflex of single
alternation, in this case hydrological regime alternation, but the deposition of
untypical fine substrates is result of eutrophication also. So, we have to be
careful with the parameter.
RO
This phenomenon exists but only on very smal rivers. For an analysis of water
bodies at river basin level it is not significant and could not be taken into
account in the first stage.
MD
agree with statements
With the exception of Germany (no comments to the table) al countries agreed with
the proposed classification system. The comment of Serbia-Montenegro indicates the
need for a better description of the decision table, especial y with respect to river
typology and location of the investigation sites. The current descriptions are only
valid for rivers with stony sediments.
3c) Criterion: migration barriers
The descriptions and threshold criteria for evaluating the possible effect of weirs and
barrages on the migration capacity of the biota refer to the conditions in the parts of
the river channel at, above, and below the in-channel structures. The estimates are
based on BEIER et al. (2002), BMLFUW (2003), CHOVANEC (2003) and observations
of the fish and benthic invertebrate ecology group of the BOKU (Department
Hydrobiology, Fisheries & Aquaculture).
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 30: Impact 3c) Disruptions of the longitudinal river continuity by weirs/barrages. Criterion:
migration barriers
1
The continuity of the river is not or only slightly disturbed by anthropogenic activities
and al ows undisturbed migration of aquatic organisms.
2
The continuity of the river is disturbed by anthropogenic activities; disturbed migration
of aquatic organisms: passage for most species in most years; no species deficit
upstream/downstream.
Description to estimate the significance of the pressure: migration barrier with
functioning passage facilities (e.g. "nature-like" bypass channel).
3
The continuity of the river is disturbed by anthropogenic activities; disturbed migration
of aquatic organisms: passage for certain species or in certain years.
Description to estimate the significance of the pressure: migration barrier with
malfunctioning passage facilities (e.g. poor designed bypass channels).
4
The continuity of the river is disturbed by anthropogenic activities; significantly
disturbed migration of aquatic organisms and sediment transport: passage for single
species occasional y (e.g. passage via ship locks, defective in-channel structures,
"compensation" flights, or terrestrial migration).
Description to estimate the significance of the pressure: migration barrier with no or not
functioning bypass facilities.
5
The continuity of the river is clearly disturbed by anthropogenic activities; no sediment
transport; significant species deficits between upstream/downstream.
Description to estimate the significance of the pressure: migration barrier completely
disrupts the continuum (large technical constructions, banks and floodplains technical y
altered).
Decision guidance to pre-classify the likelyhood (border between 2 and 3) or
significance (worse than 3) of the water body failing the good ecological status:
Threshold ratio to assess the likelihood if the Migration barrier with malfunctioning passage
water body is at risk to fail the good
facilities (e.g. poorly designed bypass
ecological status:
channels)
Threshold ratio to assess the significance of
Migration barrier with no or not functioning
the water body failing the good ecological
bypass facilities
status:
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 31: Comments of the national consultants to Table 30: Impact 3c) Disruptions of the longitudinal
river continuity by weirs/barrages. Criterion: migration barriers
Country
Comments
D
no comments to the table
A
As mentioned above the disruption of longitudinal river continuity represents a
frequent and therefore important pressure on ecological status. Concerning the
disruption of species migration, attention has to be paid to the functioning of
fish bypass channels. This issue is integrated in the decision guidance for pre-
classification and therefore the suggested threshold criteria are reasonable and
correspond to national approaches.
SK
no comments to the table
H
The criteria made on the grounds of the migration barriers are without fixing
acceptable for Hungary.
YU
no comments to the table
RO
The migration barriers have to be discussed only for migratory species; the
research studies from Romania have indicated that other species can develop
in upstream and downstream areas of hydraulic works.
MD
no comments to the table
Germany, Slovakia, Serbia-Montenegro and Moldova did not comment the table.
Austria, Hungary and Romania accepted the proposal but pointed out the
significance of migration barriers for migration species, especial y fish.
4) River engineering banks
The estimates are based on suggestions of BEIER et al (2002), BMLFUW (2003),
CHOVANEC (2003), SCHMUTZ et al. (2001) and observations of the fish and benthic
invertebrate ecology group of the BOKU (Department Hydrobiology, Fisheries &
Aquaculture).
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Table 32: Impact 4) River engineering banks
1
Bank structures correspond total y or nearly total y to undisturbed conditions, no river
engineering.
Riparian vegetation corresponds total y or nearly total y to undisturbed conditions,
minimum width of vegetation should guarantee natural functions.
% bank length (both sides) in natural state:
smal rivers to medium constrained rivers: >90%
medium to large braided, anabranching and meandering rivers: >75%
2
Re-insectioned*) banks (e.g. alterations of the bank structures due to channel
modifications); if rip-rap, then restricted to the lower 1/3 of the slope or not directly
covered by water.
Riparian vegetation covering the shore with a minimum cover of 50%; lateral extension
should guarantee important natural functions.
% bank length (both sides) in natural state:
smal to medium constrained rivers: 90 - >50%
medium to large braided, anabranching and meandering rivers: <75 - >50%
3
Re-insectioned*) banks (e.g. rip-rap with direct water contact)
Few or single row of riparian gal ery, covering <50 - 20% of the banks
% bank length (both sides) in natural state:
smal to medium constrained rivers: <50 %
medium to large braided, anabranching and meandering rivers: <50 %
4
Reinforced**) banks; significant parts of impervious bank materials (plastering),
higher bank vegetation restricted to single stands of shrubs and/or trees: <20%
% bank length (both sides) in natural state: 0
5
Reinforced**) banks; impervious bank materials (e.g. concrete wal s, sheet piling)
Nearly no to no higher bank vegetation
% bank length (both sides) in natural state: 0
*) Re-insectioned river (bank): Profile modified but not reinforced often to accommodate flood flow and access
for maintenance machinery.
**) Reinforcement: Whole or part of the river (bank, bottom) artificial y strengthened for bank protection
purposes.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Decision guidance to pre-classify the likelyhood (border between 2 and 3) or
significance (worse than 3) of the water body failing the good ecological status:
Threshold ratio to assess the likelihood if the
water body is at risk to fail the good ecological
% bank length (both sides) in natural state:
status:
Smal to medium constrained rivers:
<50%
Medium to large braided, anabranching and
<50%
meandering rivers
Threshold ratio to assess the significance of the
% bank length (both sides) in natural state:
water body failing the good ecological status:
Smal to medium constrained rivers:
<20%
Medium to large braided, anabranching and
<20%
meandering rivers:
Table 33: Comments of national consultants to Table 32: Impact 4) River engineering banks
Country
Comments
D
no comments to the table
A
Threshold criteria for pre-classification are reasonable.
SK
In Slovakian stretch - 3
H
In Hungary there is a strong intervention on most of the rivers, that is why we
regard this question as particularly significant. With the categories we can
agree without affixing of any reflexions.
YU
It is good that the quality of material that was used for bank structures has
been mentioned in the table - the structures that have been made from larger
units represent relatively sterile habitat in comparison with structures that are
composed of smal er stones.
RO
see Table 20
MD
Agree with the statements
With the exception of Germany (no comments to the table) al countries agreed with
the proposed classification system. The threshold values of the Romanian decision
table differ from the proposal, the Romanian system is more rigid.
5) Effects of water abstraction (residual water flow), proposed significance
criteria not tested for large rivers
The descriptions and threshold criteria for evaluating the possible effects of water
abstraction refer to the conditions in that part of the river channel with the minimum
residual water observed (except natural infiltration sections). Two suggestions are
given. The first estimates are in accordance with BMLFUW (2003), JÄGER (2000).
The second estimates are derived from a study of GRASSER & MOOG (2003).
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
MQRW mean annual discharge* in the residual water flow section
("Restwasserstrecke") (based on yearly recordings)
MQnatural
mean annual discharge in the natural river section (channel with
natural water flow)
MNQnatural
mean annual low discharge in the natural river section
MNQRWmean annual low discharge in the residual water flow section
NNQ
lowest observed low discharge
Table 34: Impact 5) Effects of water abstraction (residual water flow), proposed significance criteria
not tested for large rivers
1
No or only marginal water abstractions. The hydrograph corresponds total y or nearly
total y to undisturbed conditions.
2
Water abstraction present, but the residual water section of the river is without or only
minimal ecological impairment.
The amount of water abstraction does not exceed the value of the annual mean water
discharge during mean annual low flow discharge conditions (MNQRW).
Threshold ratio to asses if the water body is not at risk to fail the good ecological status:
No Water abstraction at natural lowest low flow conditions (< NNQ) and the residual
water flow corresponds to/simulates the natural annual flow regime and
MQRW = >100% MNQnatural or
monthly MQRW = >35 % monthly MQnatural.
3
Water abstraction present, residual water discharge presumably too low and thereby
with no tolerable effect on the biota. There is a risk to achieve a good ecological status.
Threshold ratio to assess the likelihood if the water body is at risk to fail the good
ecological status:
MQRW = <100% - >40% MNQnatural or
Monthly MQRW = <35 % - >15 % monthly MQnatural.
4
Total river water abstracted. Descriptive features to estimate the significance of the
pressure: no or only few residual water below the weir, but in the tail water section
some natural discharge occurs by groundwater exfiltration and/or by confluence of
tributaries.
Threshold ratio to assess the significance of the pressure:
MQRW = <40% MNQnatural or
monthly MQRW = <15 % monthly MQnatural.
5
Total river water abstracted. There is a clear risk to achieve a good ecological status.
Descriptive features to estimate the significance of the pressure: no residual water
below weir; there is no groundwater exfiltration into the tail water section and/or no
confluence of tributaries.
* Discharge (Q): The volume of water per unit time that passes a specific point on a
stream.
Decision guidance to pre-classify the likelyhood (border between 2 and 3) or
significance (worse than 3) of the water body failing the good ecological status:
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Threshold value to assess the likelihood if the
MQRW = <100% MNQnatural or
water body is at risk to fail the good ecological
monthly MQ
status:
RW = <35 % monthly MQnatural
Threshold value to assess the significance of
MQRW = <40% MNQnatural or
the water body failing the good ecological
monthly MQ
status:
RW = <15% monthly MQnatural
Table 35: Comments of the national consultants to Table 34: Impact 5) Effects of water abstraction
(residual water flow), proposed significance criteria not tested for large rivers
Country
Comments
D
no comments to the table
A
Threshold criteria are reasonable and correspond to national approaches.
SK
In the Slovak stretch (the Danube beside old Danube River bed 1851,6-
1811 rkm) between 1-2; Old Danube River bed 4
H
The water abstraction on surface waters is regulated since about 120 years in
Hungary. There is an amount of water, which is the 75% of the long term lowest
discharge of August, that can't be abstracted. This amount of water has always
served for the ecological water supply and the navigation. For the Danube this
discharge is set on a higher amount (100%) because of the navigation. The
water abstraction has never caused a problem on the River Danube.
Concerning the five water abstraction types, we absolutely accept your
suggestion. Here we add that the water abstractions in Hungary have a
particular situation because of the downstream location. So Hungary has
always had to husband with the water resources, where the months in summer
signify the most remarkable problems. Regarding our little rivers we would
prefer the monthly mean discharge for the representation of the effects of water
abstraction.
We also accept the suggestion for the threshold values.
YU
clear table
RO
see Table 20
MD
Agree with the statements. But preferably the second estimate of Grasser &
Moog study
With the exception of Germany (no comment to the table) al countries agreed with
the proposed classification system. The consultant of Romania presented a different
system.
6) Effects of hydropeaking (incl. sudden flow reduction)
The descriptions and threshold criteria for evaluating the possible effects of
hydropeaking refer to the conditions in that part of the river channel with the
maximum hydropeaking ratios observed. The estimates are based on suggestions of
BEIER et al. (2002), BMLFUW (2003), CHOVANEC (2003), JÄGER (2002) and the
Austrian system for pre-classifying the ecological status of the AQEM and STAR
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
projects (http://www.aqem.de, http://www.eu-star.at). The table is given for several
stream types. National consultants were encouraged to focus on giving comments to
large rivers.
HQPF high flow during flood pulse (peak operation)
NQPF low flow between flood pulses
Table 36: Impact 6) Effects of hydropeaking (incl. sudden flow reduction)
1
Natural hydrograph corresponds total y or nearly total y to undisturbed conditions, no
hydropeaking. If some hydropeaking effects (e. g. caused by tributaries) occur, the total
river bottom (100%) stays water-covered and the ratio of peak discharge (HQPF) to low
discharge (NQPF) does not exceed the factor 1.5.
2
Hydropeaking without or only minimal ecological impairment. River morphology only
minor disturbed and near to nature, with "shelters" available. Hydropeaks are not
suddenly released (e.g. intermittent storage reservoir) and at least 80% of the river
channel are covered by water during low flow and the average flow velocity is not
reduced more than at least 20%.
Threshold ratio to assess if the water body is not at risk to fail the good ecological status:
Constrained river sections: The ratio of peak flow (HQPF) to low flow (NQPF) does not
exceed the factor 3; [peak discharge: low discharge (HQPF:NQPF) <3].
Braided/anabranched rivers: The ratio of peak flow (HQPF) to low flow (NQPF) does not
exceed the factor 2; [peak discharge: low discharge (HQPF:NQPF) <2].
Large rivers: peak discharge: low discharge (HQPF:NQPF) <?
3
Hydropeaking with only moderate ecological impairment; river habitats impaired, parts
of the river fal dry during low flow, but "shelters" available.
Threshold ratio to assess the likelihood if the water body is at risk to fail the good
ecological status:
Constrained river sections: HQPF:NQPF 3 - <10.
Braided/anabranched rivers: HQPF:NQPF between 2 - <4
Large rivers: HQPF:NQPF ?.
4
Hydropeaking remarkably affects the ecological status.
Threshold ratio to assess the likelihood if the water body is at risk to fail the good
ecological status:
Constrained river sections: HQPF:NQPF>10 - <50.
Braided/anabranched rivers: HQPF:NQPF between 4 - <10
Large rivers: HQPF:NQPF ?
5
Hydropeaking causes a total disruption of the environment and the biota.
Threshold ratio to assess the likelihood if the water body is at risk to fail the good
ecological status:
Constrained river sections: HQPF:NQPF >50
Braided/anabranched rivers: HQPF:NQPF >10
Large rivers: HQPF:NQPF ?
Decision guidance to pre-classify the likelyhood (border between 2 and 3) or
significance (worse than 3) of the water body failing the good ecological status:
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
Threshold ratio to assess the likelihood if
the water body is at risk to fail the good
ecological status:
Constrained river sections:
High discharge : low discharge (HQPF:NQPF) 3 -
<10
Braided/anabranched rivers:
High discharge : low discharge (HQPF:NQPF) 2 -
<4
Large rivers:
High discharge : low discharge (HQPF:NQPF) >?
Threshold ratio to assess the significance
of the water body failing the good
ecological status:
Constrained river sections:
High discharge : low discharge (HQPF:NQPF) >10.
Braided/anabranched rivers:
High discharge : low discharge (HQPF:NQPF) >4
Large rivers:
High discharge : low discharge (HQPF:NQPF) >?
Table 37: Comments of the national consultants to Table 36: Impact 6) Effects of hydropeaking (incl.
sudden flow reduction)
Country
comments
D
no comments to the table
A
Suggested threshold criteria are acceptable for a pre-classification. Criteria for
large rivers (Danube) need as mentioned anyway further expert discussion.
SK
In the Slovak stretch of the Danube 1
H
According your statements above we do not real y have experience in
analysing the effects of hydropeaking. Several studies have been realised
about the impacts of the edifices and their function of the planned hydroelectric
power station for the stretch between Gabcikovo and Nagymaros which
documents are accessible. For further information an ecological research is
needed.
In default of other specifications we agree with the table above until there does
not exist a document based on deep researches.
YU
no comments to the table
RO
It is recommended to use the water level gradient, because it is more
representative for hydropeaking, having a lower variability from one river to
another than the peak flow, see Table 20.
MD
agree with the statements
With the exception of Germany and Serbia-Montenegro (no comments to the table)
and Romania al countries agreed with the proposed classification system. Hungary
sees the necessity of more research work on the effects of hydropeaking on the
Danube biota. Romania recommended to use the water level gradient for
documenting the hydropeaking effects. A value for large rivers, where the
international consultants did not make a suggestion, was not proposed by any
country.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
8.
SUMMARY
Among the "universe of drivers" that may cause detrimental effects to the hydro-
morphological conditions of the Danube River hydropower generation is seen as the
most important driving force, fol owed by flood defence measures and navigation as
the tertiary (Table 6). Fisheries, removal of plants/animals and inshore habitat
management are not regarded as relevant drivers with remarkable pressures on the
Danube environment. Two more drivers have been added by the Hungarian
consultants, the inter basin transfer and the water intake. Al together eight drivers
have been regarded as anthropogenic activities that may have an environmental
effect on the Danube. These relevant drivers that cause a remarkable hydro-
morphological pressure on the Danube River environment are (in order of their
relevance): hydropower generation, flood defence, navigation, gravel extraction,
water abstraction, outdoor recreation, fisheries, inter basin transfer, and water intake.
Three countries have already started with the process of identifying pressures
(Germany, Austria, and Hungary). In Romania this process is under development.
Slovakia, Croatia, Serbia-Montenegro, Bosnia-Herzegovina and Moldova have not
started with the process of identifying pressures.
Al proposed pressures of the driver "hydropower use" have been confirmed
(Table 11). No additional pressures have been suggested by the national
consultants. The "disruptions of the longitudinal connectivity" are seen as the most
important pressure of this category fol owed by the "alteration of the hydraulic
characteristics" which has been ranked as the major pressure in Germany, Austria,
Romania. Al other categories have been indicated with lesser importance ("alteration
of the river course and channel form", "disruptions of lateral connectivity", and
"alteration of the hydrological (discharge) regime").
Al suggested pressures of the driver "flood defence" (Table 9) have been
confirmed as impacts induced by flood protection measures. "Alteration of the river
course and channel form/profile" is regarded as the most important pressure. The
categories "flood defence dams, set-back embankments, dykes", "alteration of the
hydrological/hydraulic characteristics" and "alteration of the bank vegetation and
banktop land use" fol owed as major pressures.
Al proposed pressures driven by "navigation impact" (Table 10) have been
confirmed. No additional pressures have been suggested. In most countries the
"alteration of the hydrological/hydraulic characteristics" has been voted as important
pressure, fol owed by "alteration of the river course and channel form/profile",
"disruptions of lateral connectivity" and "alteration of morphological features/habitats".
"Gravel extraction" has been quoted as a driver of minor importance (Table 13)
although the consultants from four countries would expect "modifications of river
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
channel, in-channel habitats and banks". Three nominations noticed the "alteration of
amount and composition of the bed sediments" as noticeable pressure. No new
category of pressures induced by gravel abstraction was added.
Al proposed pressures with respect to the driver "water abstraction" have been
confirmed by the national consultants (Table 12). No additional pressures have been
added. Only the first five pressure categories have been seen as possibly important,
no ranking was performed.
Pressures induced by "outdoor recreation" were nominated as of minor relevance
by Austria and Hungary (Table 14).
With respect to identify the likelihood and/or the significant impact of a pressure the
German contribution focuses on three topics: 1) morphological degradation, 2)
longitudinal continuity and 3) water abstraction. The criteria are published in a LAWA
AO paper (2003).
Romania presents a table for assessing six types of significant hydromorphological
pressures: 1) Disruptions of the longitudinal river continuity by weirs, barrages, sil s;
2) Disruptions of the lateral river continuity by river engineering connectivity to flood
plains (dykes, agricultural works, fish farming works etc.); 3) River engineering
banks regulation/consolidation; 4) Navigation channel; 5) Water abstraction, water
out-takes, flow deviation; 6) Dams discharges hydropeaking. Threshold values are
given for the likelihood and for the significance of a pressure to fail the environmental
quality goal (Table 20).
A set of eight tables with proposals how to classify a pressure as significant impact
has been commented by national consultants. The impacts of the fol owing pressures
have been described: 1) Disruptions of the lateral river connectivity by river
engineering connectivity to flood plains, sidearms and backwaters; 2) Navigation
channel; 3) Disruptions of the longitudinal river continuity by weirs/barrages (3 a)
height of the in-channel structures; 3 b) Composition of channel substrates; 3 c)
Migration barriers); 4) River engineering banks; 5) Effects of water abstraction; 6)
Effects of hydropeaking.
The tables are considered as a tool for estimating the impacts of a variety of
hydromorphological pressures with special emphasis to identify significant pressures.
The tables use a three-tiered procedure: 1) a descriptive indication of the likely-to-be
relationship of a pressure's impact along a gradient of five steps of status classes, 2)
criteria for an assessment of the likelihood and 3) criteria for an assessment of the
significance that surface water bodies within the River Basin District wil fail to meet
the environmental quality objectives set for the bodies under Article 4 of the WFD.
This approach can serve as a first step which has final y to be fol owed by biological
investigations to classify the impacts.
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MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
The fol owing table summarises the reaction of the national consultants to the
procedure proposed. Germany gave no comments and refers to the LAWA paper.
Romania referred to the national procedures. Yugoslavia did not respond to three
options. Slovakia and Moldavia gave no comment to one suggestion. The majority of
the recommended procedure have been accepted by Austria, Slovakia, Hungary,
Yugoslavia and Moldavia.
Table 38: Summary of responses of national consultants to the procedure proposed
Country/
Comments
Pressures
1
2
3a
3b
3c
4
5
6
D
nc
nc
nc
nc
nc
nc
nc
nc
A
SK
nc
H
, op
YU
nc
nc
nc
RO
op
op
op
nr
ru
op
op
op
MD
nc
Legend: nc...no comment;
...agreed; op...own proposal; nr...not relevant; ru...of
restricted use
Summarising the outcome of questionnaire part C we have to state that three
methods exist to carry out an estimation of the likelihood that a given section (water
body) of the Danube River wil fail to meet the environmental quality objectives:
· the German LAWA methodology with a focus on general morphological
degradation, longitudinal continuity and water abstraction
· the Romanian procedure as contributed to the recent UNDP/GEF Danube
Regional Project
· the proposal of the international consultants of this UNDP/GEF Danube
Regional Project which was developed in co-operation with Austrian
scientists, technicians and the state and federal administration
In a preliminary analysis it can be stated that the Romanian way comes quite near to
the international consultants' proposal. As there is anyway the necessity to adapt any
decision system to the local typological conditions the international consultants see
no obstacles to harmonise these two methodologies.
The German methodology is based on a existing scheme of classifying ,,structure
quality classes", and besides on more simple descriptions that cover a smal er aspect
of potential pressures. The ,,structure quality class" approach is only used in
Germany and Austria, but the system has never been applied at the Danube in
Austria. Nevertheless a comparison of the German and Austrian ,,structure quality
class" approaches is possible although some methodological features do actual y
-43-
MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
differ. But the interpretation of the outcome of the ,,structure quality class" result
clearly differs between the countries. According to the German system river stretches
are classified to have a significant pressure if they are classified with a ,,structure
quality class" of 6 or 7 out of a system with categories between 1 (very good status,
reference) and 7 (far from nature). The Austrian philosophy in contrast would classify
a water body to have a significant pressure if a ,,structure quality class" >5 is
recorded.
With respect to ,,longitudinal continuity" the German system gives no more detailed
information: river stretches are classified to have a significant pressure if the
longitudinal continuity is disrupted for biota (fish and benthic invertebrates) by
upstream and/or downstream barriers. As there is no definition about when a
continuity is disrupted it may be possible to harmonise the methods.
In the case of water abstraction the German procedure classifies river stretches to
have a significant pressure if less than 2/3 of the average low flow (MNQ) is
remaining if they have no legal residual water requirement, and if significant impacts
on the biota are to be expected. This value comes quite near to the 40% MNQ
threshold that has been proposed by the international consultants of the current
UNDP/GEF Danube Regional Project.
Consequently the next step must be to validate and to harmonise the three
methodologies. This procedure should be done in a working group including at least
experts from the three protagonists.
After a common procedure to carry out an estimation of the likelihood that a Danube
water body wil fail to meet the environmental quality objectives has been developed,
this methodology needs to be adapted to the type-specific needs of the different
water bodies.
Not until these activities have been successful y undergone it wil be possible to start
with a stress and impact analysis with particular attention to hydromorphological
conditions in the entire stretch of the Danube River.
9.
OUTLOOK
The planned output of step 2 was a report on "Stress and impact analysis with
particular attention to hydromorphological conditions in the Danube River". As the
activities of step 1 of the UNDP/GEF Danube Regional Project have been quite time
consuming the consultants were not able to include the assignment of step 2 in their
working program. Due to the lack of information on determining hydro-
morphological y relevant drivers, pressures and the assessment of their impacts on
-44-
MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
the biota, most of the methodologies were developed during the GEF project and
need to be tested now.
To apply these tools on the Danube River for assessing the likelihood and the
significance if a water body is at risk to fail the good ecological status it wil be
necessary to
1. harmonise the different methodologies and consolidate the different approaches
in one common procedure to carry out an assessment of the likelihood that a
Danube water body wil fail to meet the environmental quality objectives,
2. perform methodological tests about the functionality of this tool,
3. sub-divide the Danube in a system of section types and water bodies,
respectively, and
4. to adapt the methodology to type-specific conditions of a water body (if
necessary).
10. REFERENCES
The questionnaires were based on the fol owing references:
Baden-Württemberg: FLEISCHHACKER, T. & K. KERN (2002/2003): Vorläufige Einstufung der
Oberflächengewässer nach Wasserrahmenrichtlinie in Baden-Württemberg, geändert
am 22.1.2003.
BEIER, U., DEGERMAN, E. & H. WIRLÖF (2000): Data input to the ACCESS-2000© database
FIDES (Fish Database of European Streams). The FAME project. 2002-06-04.
BMLFUW VIENNA (2001): Vorschläge für die Definition signifikanter Belastungen (Stand Juni
2001): 2 p.
BMLFUW VIENNA (2003): Runder Tisch "Hydromorphologie" Details für Impulsreferate
3. Juli 2003.
C.I.S "IMPRESS" GUIDANCE (2002): Guidance for the analysis of Pressures and Impacts in
accordance with the Water Framework Directive. Final Version 5.3: 04 December
2002: 152 pp.
CHOVANEC, A. (2003): Tischvorlage BMLFUW am 3.7.03 Scoring system
"Hydromorphologie"
German and Austrian experiences (pers. comm.)
GRASSER, U. & O. MOOG (2003): Das Makrozoobenthos als Indikator des "Ökologischen
Zustandes" von Restwasserstrecken Ergebnisse der Auswertungen von 249
Untersuchungsstel en (1983-2002) im Hinblick auf die Beeinträchtigungen der
Abflussverhältnisse.- Natur in Tirol 12: Ökologie und Wasserkraftnutzung, Innsbruck:
111-121 (ISBN 3-902-169-03-6).
JÄGER, P. (2002): Hydromorphologische Fließgewässeraufnahme von Salzburg 2003,
Gewässerschutz Salzburg
LAWA (2002): German Guidance Document for the implementation of the EC Water
Framework Directive. 27.02.2002: 125pp.
-45-
MOOG & STUBAUER: Stress and Impact Analysis Methodological Approach
LAWA AUSSCHUSS OBERIRDISCHE GEWÄSSER (2003): Kriterien zur Erhebung von
anthropogenen Belastungen und Beurteilung ihrer Auswirkungen zur termingerechten
und aussagekräftigen Berichterstattung an die EU-Kommission Stand 12/03/2003:
48pp.
MLIM-EG (2003): Typology and reference conditions for surface water bodies. Final working
paper, 13 May 2003: 13pp.
SCHMUTZ, S., MUHAR, S. & G. EGGER (2001): Definition des guten Zustandes (gemäß WRRL)
für die Flusslandschaftstypen der Möl . Positionspapier zu Teilmodul 3/T15; KLF-
Projekt: Flusslandschaften Österreichs
11. QUESTIONNAIRES
The questionnaire is divided into three parts to be fil ed in for methods in use or
planned to describe A) drivers, B) pressures and C) impacts of the Danube River.
The original questionnaires are attached in the annex of this report.
ANNEX
-47-
ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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indicate
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1 The list has been compiled using the C.I.S "Impress" guidance (Guidance for the analysis of
Pressures and Impacts in accordance with the Water Framework Directive)", the MLIM working
paper from 13 May 2000 "Typology and reference conditions", C.I.S Project 2.1 Guidance on
the analysis of pressures and impacts (Environment Agency & LAWA), ICPDR Draft-2 DOC-
138 15_Oct.-2001, and other German and Austrian experiences.
-56-
ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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Modifications of river channel, in-channel habitats and banks for
recreation purposes as there are fishing (facilities; houses; bank
alterations), recreational navigation (e. g. harbours), boating,
rafting, water ski ng etc.
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-60-
ANNEX 1 - QUESTIONNAIRE: IDENTIFYING HYDROMORPHOLOGICAL PRESSURES ON THE DANUBE RIVER, PART A&B
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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ANNEX 4 HAIDVOGL ET AL.: DESCRIPTION OF REFERENCE CONDITIONS OF THE AUSTRIAN DANUBE
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