Workshop on surface Water body delineation. Hydromorphology

European Union Water Initiative plus
for Eastern Partnership
© iStockphoto.com/ansonsaw
Support of Water Policy Reforms
towards Integrated Water Resources Management
WORKSHOP ON
SURFACE WATER BODY DELINEATION
- HYDROMORPHOLOGY
(Armenia, Azerbaijan, Belarus, Georgia)
Robert Konecny, Georg Wolfram, Alexander Zinke
Kyiv, 24-25 May 2018

Water status is defined by:
 Biological elements
 Chemical and physico-chemical elements supporting the biological elements
and
 Hydromorphological elements supporting the biological elements
 Hydrological regime
• quantity and dynamics of water flow
• connection to groundwater bodies
 River continuity
• migration of aquatic species
• sediment transport
 Morphological conditions
• channel patterns, river depth and width variation
• flow velocities, substrate conditions,
• structure and condition of the riparian zone
WFD ANNEX V: QUALITY ELEMENTS
2

TOP-DOWN
FROM THE
DOLOMITE
MOUNTAINS…
… TO THE
PANNONIAN
PLAIN …
… the Drava crosses the strong interests of many
sectors.
Wien, 18. 5. 2014
Photo: Revital
Photo: Zinke

HYMO DATA ARE NEEDED TO DEFINE
THE TYPE-SPECIFIC CONDITIONS
Identification of significant hydromorphological pressures
at least at 3 levels:
• no pressure
• pressure but not significant
• significant pressure
4

RISK ASSSESSMENT FOR EACH WB
Likelihood, that a water body will fail to achieve the environmental
objectives (good status!) due to the impact on biology resulting from
significant pressures
At least 2 classes required:
 1 not at risk
 2 possibly at risk (lack of data & information on impact of pressure)
 3 at risk
Risks specified to specific pressures/impacts facilitate the
subsequent design of restoration measures and the monitoring of
success
5

6

DESIGNATION (DELINEATION) OF HMWB
WB is substantially changed in its character
Proof needed that hydromorphology is so much altered and that the
biological QE are failing good status.
For achieving GES, (restoration) measures would require changes in
hydromorphological charcteristics and have a significant adverse
effect on environment and use(s):
navigation, power generation, drinking-water supply, irrigation, land
drainage, flood protection, recreation
Art. 4.3. WFD requires detailed information on hymo pressure(s) and
the causing driver(s).
7

DESIGNATION (DELINEATION) OF HMWB
HMWB refers to river sections subject to:
• Impoundments and storage reservoirs
• Regulated stretches in villages and towns, if no space!
• Flow variations due to hydropeaking (but only if the change of
operational mode is the only possibility to restore good status)
• Water bodies failing GES due to water abstraction to fill storage
reservoirs for peak load production
As a result, the majority of AT stretches impacted by water
abstraction was not designated as HMWB: The GES can be
achieved via restoration of the „ecological flow“.
8

HYMO STATUS ASSESSMENT
Information is needed for selection of representative monitoring
site(s): where to set it/them?
9

DEVELOPMENT OF POM: DESIGN OF
TECHNICAL RESTORATION MEASURES
Detailed info on hymo pressures/impacts (exact location/
segment magnitude/extent, …) allows:
• calculation of restoration costs on an overview level
• clear identification of the „causer“
• assessment of magnitude of possible negative effects on use
(i.e. loss in electricity generation) … also relevant for HMWB
designation, exemption
• Selection of the most cost-effective set of measures
10

Upper
Austrian
Drava
Photos: Revital

Measures for
better river
management
 Verbund Hydro Power
Granulometric Bed Improvement
River Bank Restoration
Optimising the Regulated Bed
Improving connectivity at groynes
Fairway Adjustment (dredge & dump)
 Kovacs
Side-arm Reconnection

HOW TO START?
Analysis of the general situation:
Main DRIVERS in AT Main PRESSURES
Hydropower interruptions of river continuity
Flood protection morphological alterations of banks /soil
Navigation Impoundments /reservoirs
Urban development water diversion /abstraction
(Agriculture) hydro peaking
13

Organic
Pollution
Nutrient
Pollution
Hazardous
Substances Pollution
Hydromorphological
Alterations
 Plus: Transboundary GW bodies of basin-wide importance
International Danube Basin Plan (WFD)
Hydromorphological
Alterations
River and Habitat Continuity Interruption (dams)
Disconnection of Adjacent Floodplains (dikes)
Hydrological Alterations (diversion; peak operation)
Future Infrastructure Projects
Key Drivers: Hydropower, Flood Protection, Navigation, Water Supply

15

HYDROLOGICAL ALTERATIONS AND
CONTINUITY INTERRUPTIONS
Why exact location of pressure?
• Easily available information (databases, licensing documents,
project documentations, …)
• Basis for water body delineation
• Basis for biological monitoring on impact (representative site)
• Basis for developing the Programme of Measures
• Overlapping alterations – multiple pressures
16

HYMO PRESSURES: TYPES AND SCALES
Pre-define the river stretches: 500m proved to be suitable!
• Pragmatic scale to identify every single alteration and
aggregate the info
• Show morphological improvement within a WB, even if
ecological status remains
• Easy updating after restoration or new alterations
17

THRESHOLDS FOR SIGNIFICANCE OF
PRESSURES
Definition of hydromorphological conditions for „high status“:
• Absence of any hydromorphological pressure
• Hydromorphological conditions, under which biological quality elements
can achieve “high status” (minor pressures tolerable)
Guiding values for hymo conditions for „good status“:
Allowed extent of pressure, so that biological status is still “good”:
• Define the hydromorphological conditions, under which biological quality
elements can achieve “good status” (→ Combine Hymo Assessment with
Biological Monitoring)
If hymo pressures exceeding the pre-defined guiding values for
“good status”: then consider as significant pressure!
18

ASSESSING HYDROLOGICAL ALTERATIONS –
WATER ABSTRACTION
Register and assess:
- All water stretches between abstraction point and return of flow
- in case of diversions: all water stretches between abstraction point and
next confluence with a larger river
Ordinance on Ecological Status Assessment:
• Only marginal abstraction (defined values of E-Flow) → high status
• Basic flow + dynamic share (defined values of E-Flow) → good status
• If criteria for good status are exceeded: significant water abstraction
19

ECOLOGICAL MINIMUM FLOW
Achievement of GES depends on two aspects:
Basic flow must be available in a water body at all times to ensure
• preservation of WB type and habitats – natural mean daily low flow (NQt)
• River continuity - minimum depth and minimum flow velocity
Dynamic share reflecting the natural discharge dynamics over the year to
ensure
• natural bed-sediment relocation, type-specific substrate,
• sufficient stream velocity in times of spawning migrations
• different habitat demands of individual age classes of key organisms
• type-specific oxygen and thermal conditions
• recommended value: 20% of natural discharge
20

ASSESSING HYDROLOGICAL ALTERATIONS –
HYDRO PEAKING
This refers to all water stretches with surge/down-surge phenomena
caused by (pumped) storage power plants
• No or only marginal surge/down-surge phenomena: high status
• Maximum ration of 1:3 between downsurge and surge, or
• at least 80 % of river bed covered during downsurge: good status
If criteria for good status are exceeded: significant pressure
21

Monotonous river courses and deficits in habitats
Populations stressed by strong hydro-peaking
Blocked longitudinal migration
Impacts of river engineering and hydropower
use despite restoration successes
Figure: LIFE
monitoring report

ASSESSING HYDROLOG. ALTERATIONS:
IMPOUNDMENTS / RESERVOIRS
Assess every river stretch with an anthropogenic reduction of the mean
flow velocity in the cross-section to 0.3 m/s at annual mean flow
• Only occasional anthropogenic reductions of the mean flow velocity and only
at very short stretches → high status
• Anthropogenic reductions of the mean flow velocity in the cross-section at a
rate of below 0.3 meters per second at annual mean flow (MQ) occur only at
very short stretches. → good status
Impoundments ecologically relevant:
rivers > 100 km² catchment size: 500 m length
rivers 10 – 100 km² catchment size: 100 m length
If criteria for good status exceeded: significant pressure
23

ASSESSING RIVER CONTINUITY
Assess causes of a barrier for aquatic fauna migration and sediment:
- Each artificial (and natural) structure
- Each stretch with water abstraction
• Unhampered migration of type-specific aquatic organisms and the
natural transport of sediments in the streambed → high status
• Anthropogenic migration barriers occurring in the natural fish habitat
must be passable for fish all year long. Human impact on habitat
connection shall only be marginal. → good status
Each single migration barrier (e.g. >1m) is a significant pressure
24

ASSESSING RIVER CONTINUITY
Verify each potential migration barrier via field check
Passability depends on height and design of stucture, its supply
with water, its connection with up- and downtream water body
25

Restoration of the river continuity
Fish pass by 2021
Fish pass by 2015
Fish passage exists

HYDRO BARRIERS AND RIVER CONTINUITY
ALONG THE INTERNATIONAL DRAVA RUN
24 hydrodams: 0.1 – 126 MW
1 in Italy
12 in Austria (1 peak)
8 in Slovenia (2 peak/bypass)
3 in Croatia (3 peak/bypass)
Fish passes: Few functional /
operating in 2014
New fishpass: Rottau dam (Möll river)
Edling dam (Drava river) Photos: Zinke

ASSESS RIVERBED DYNAMICS
Indicate in 5 classes if river bed dynamics are
• Unrestricted
• Limited by measures to stabilise the river bed
• Altering the natural grain size distribution, or
• suppress or inhibit bed dynamics at individual points or in entire
sections
Note: impounded river stretches are always assessed with class 4
28

ASSESS BANK DYNAMICS
Bank dynamics indicate in 5 classes a river's capacity to
• change and reconfigure the typical river course and
• develop type-specific bank structures that are crucial for habitat
diversity, such as
• undercut and glide slope banks
• erosion banks
• banks with flat and steep embankments
• wash-outs
• woody plant structures and root network in the riparian zone.
The application of bank structuring and protection measures limits
the capacities of a river to develop type-specific bank structures and
to form its riparian zone.
29

NATIONAL HYMO METHODOLOGY
Need to develop an assessment system that fits to national diversity of river and
describes 5 hymo classes for all river types
• with defined type-specific hymo reference conditions
• according to bioregions, sea level and catchment sizes
in terms of
 hydrological conditions
 planform
 slope and width of river
 flow characteristics
 instream structures
 bank structures
 bed and substrate conditions and
 biological reference conditions
Assess permanent impacts and their effect fo each river type.
Apply worst-case principle
30

SUMMARISE ASSESSMENT
Define high, good, moderate, poor and bad hymo status in terms of
• Morphological alterations (bank and bed dynamics)
• Hydrological alterations (water abstraction, hydropeaking,
impoundment)
• River continuity interruptions (artificial barriers restricting fish
passability)
• Risk assessment
…and summarise assessment results for each river.
Set up national databases with maps: online access to registered
users!
31

Restoration at
Obergottesfeld
Opening in 2011
Rework in 2014
Photo. Zinke Photo. AKL / Tichy
Photo: Revital

Flood Protection
Drava projects have led
to improved…
Retention Areas
Morphological Dynamics
Aquatic Habitats
Recreation Areas
Non Aquatic Habitats
River Widening at Obergottesfeld

Hanging structure with tires Embedding crushed rocks Binding soil layer on gravel
Reshaping and willow rolls Vegetation growth after several seasons
Rehabilitation of impounded sections
Example Feistritz reservoir – Rehabilitation of the dike crest
© Verbund AHP - DHI Sabine Käfer 2009

öö
Example for Water Body Delineation: Danube, Austria
WB4
Type
Upper Danube 2 Type Upper Danube 3
Eco-/bioregion boundary
WB5

LET‘S DO SOME PRACTICAL REFLECTIONS
37

Workshop on surface Water body delineation. Hydromorphology

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