existing measures & options for the future in large river ...€¦ · existing measures &...
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Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 1 / 29
Compensatory habitats
Existing measures & options for the future
in large river impoundments
Clemens Ratschan,
Wolfgang Lauber, Martin Mühlbauer, Gerald Zauner
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 2 / 29
Compensation for loss of habitat due to
• (River Regulation)
• (Navigation)
• (Hydropeaking, Residual flow, ..)
• Hydropower - Impoundments
Traun, 48°N 14°E Koppi, 48°N 140°E
figu
re: V
erb
un
d
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Main effect for indicator „fish“
Loss of key habitats for rheophilic fish- spawning habitats
- habitats for early life stages
embryo, larva, juveniles (0+, 1+)
Small fish biomass ≈ small populations
free flowing free flowing head of imp. impoundment
Fis
h b
iom
ass [
kg /
100 m
]
0
1
2
3
4
5
6
7
8
K.O. Fish Index Austria
1985-87 2007-2014
n=115
n=49
n=213
n=111
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Options for compensatory habitats
Figure: Boku Wien, IHG
head of
impoundment
impoundment
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Measures at the head of an impoundment
Danube downstream HPP Ottensheim-Wilhering
side arm (800 m)
further measures planned and being built
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Measures at the head of an impoundment
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Measures at the head of an impoundment
Inn downstream HPP Ering-Frauenstein
widening, island / side arm, backwater
(picture: under construction)
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 8 / 29
Measures in the impoundment
• many examples
• limited longevity
• effect mainly for ubiquitary species
• limited contribution for
„good ecological potential“
Danube impoundment
Jochenstein
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Measures between impoundments = fishways
What is a „NATURE-LIKE FISHWAY“?
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Key factors for functional habitats
• Slope
• Morphology
• Dynamic flow
• Sediment dynamics
• Factor time (longevity, maintainance)
± state of the art in
„nature-like fishways“
poorly implemented
hardly implemented
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Section nature-like bypass channel (Inn)
pot. spawning habitat
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habitats for juveniles
Section nature-like bypass channel (Inn)
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MNQ MQ QA bordvoll
Standard Standard Standard Standard
Gefälle %o 1,10 1,10 1,10 1,10
Sohlbreite m 2 2 2 2
Böschung Flachufer 1:… 8 8 8 8
Breite Wasserspiegel m 8,8 8,8 16,0 19,1
Wassertiefe (Tiefenrinne) m 0,80 1,30 1,60 2,80
Fläche m² 4,6 10,4 15,1 36,6
benetzter Umfang m 9,8 14,6 17,4 20,8
hydraulischer Radius m 0,47 0,71 0,87 1,76
mittl. Fließgeschw. m/s 0,50 0,66 0,75 1,21
Abfluss m³/s 2,3 6,9 11,4 44
mittl. Schleppspannung N/m² 5,1 7,7 9,4 19,0
Schleppspannung erhöhtes MW (Bereich Böschungsknick) 12,9
Innwasserstand
Profil bzw. Gefälle
"Hohe Laichplatzqualität" & "mittlere bis hohe
Qualität" als Jungfischlebensraum
Qmax to maintain key habitats at the shore
Maintainance of high quality
spawning habitats and
medium-high juvenile habitats:
Flushing with ≥ 40 m3/s needed
(sections with low valley slope)
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Sedimentation of habitats at the shore
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Sedimentation of habitats at the shore
Tau 40-35-30-25m³/s
40
35
30
25
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Measures parallel to an impoundment
• Very high restoration potential in impounded river basins
(if area is available)
Slope
Morphology
Spacial dimension
Flow dynamics
Sediment dynamics
• Dynamic dotation from the impoundment + sediment management
and / or
• Integration of tributaries (space, base flow, flow dynamics, sediments)
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 17 / 29
Measures parallel to an impoundment
Inn HPP Ering-Frauenstein
Dynamic bypass channel, 2,6 km
Dynamic dotation 2-10 m3/s
Sediment management
(picture: under construction)
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Measures parallel to an impoundment
Danube HPP Ottensheim-Wilhering
Bypass channel: 14,2 km
MQ = 3,4 m3/s, MJHQ > 20 m3/s
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 19 / 29
Measures parallel to an impoundment
Danube HPP Ottensheim-Wilhering
Bypass including tributary Aschach
MQ = 6 m3/s, MJHQ =140 m3/s
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 20 / 29
Measures parallel to an impoundment
Danube HPP Ottensheim-Wilhering
Bypass including tributary Innbach
MQ = 17 m3/s, MJHQ 235 m3/s
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 21 / 29
Combination of measures – habitat network
restoration &
protection
of fish
population
spawning
Danube
HPP Ottensheim-Wilhering
+ backwater
+ further
tributaries
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 22 / 29
Combination of measures – habitat network
spawning & juvenile habitats (phytophilic species)
spawning juvenile habitats
(rheophilic species) (rheophilic species)
Inn HPP Ering-Frauenstein
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 23 / 29
Compensatory habitats,
migrations and fish protection
• Goal: Restoration of fish populations in series of impoundments
• Presently: Massive habitat deficits
• Danube catchment / Austria:
Populations of long-distance migrating fish species extinct
-> lower need for very highly efficient upstream passage
• Technical or nature-like approach?
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 24 / 29
impooundm
ent
impooundm
ent
impoundm
ent
impoundm
ent
A
technical fishway+protectionB
fishway+compensatory habitats
Hypothetical ScenariosRestoration of fish populations
in medium-sized / large rivers
intensive
migration
non-intensive
migration
key habitat
upstream
key habitat
downstream
turbine passage
mortalityx
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 25 / 29
fishw
ay
fishw
ay
fishw
ay
byp
ass c
hannel
byp
ass c
hannel
fishw
ay
Instr
eam
habitat
Instr
eam
habitat
rack+
bypass
rack+
bypass
rack+
bypass
A
technical fishway+protectionB
fishway+compensatory habitats
intensive
migration
non-intensive
migration
key habitat
upstream
key habitat
downstream
turbine passage
mortalityx
Hypothetical ScenariosRestoration of fish populations
in medium-sized / large rivers
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 26 / 29
Sta
u
migrations
upstream
migrations
downstream
xx
x
migrations
downstream
xxx x
xxx
migrations
upstream
A
technical fishway+protectionB
fishway+compensatory habitats
intensive
migration
non-intensive
migration
key habitat
upstream
key habitat
downstream
turbine passage
mortalityx
Hypothetical ScenariosRestoration of fish populations
in medium-sized / large rivers
20-40 km
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 27 / 29
FA
H
FA
H
fishw
ay
Sta
uS
tau
Sta
u
Rechen+
FAB
Rechen+
FAB
rack+
bypass
migrations
upstream
migrations
downstream
xx
x
migrations
downstream
xxx x
xxx
migrations
upstream
A
technical fishway+protectionB
fishway+compensatory habitats
intensive
migration
non-intensive
migration
key habitat
upstream
key habitat
downstream
turbine passage
mortalityx
migration distances: lower
mortality adults: low
mortality juveniles: low
key habitats: high
recruitment: high
population size: high
risks: lower
investment: lower
energy loss: lower
[QFAH]
Hypothetical ScenariosRestoration of fish populations
in medium-sized / large rivers
migration distances: high
mortality adults: (low)
mortality juveniles: higher
key habitats: low
recruitment: low
population size: low
risks: higher
investment: higher
energy loss: higher
[QFAH+QFAbH]
Huge positive effects for other biota
(incl. humans)
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 28 / 29
Rechen+
FAB
Rechen+
FAB
migrations
upstream
migrations
downstream
xx
x
migrations
downstream
xxx x
xxx
migrations
upstream
A
technical fishway+protectionB
fishway+compensatory habitats
intensive
migration
non-intensive
migration
key habitat
upstream
key habitat
downstream
turbine passage
mortalityx
(Maximum) Variant B+
fishway + compensatory habitats
+ technical fish protection
still possible later
if feasible
& neccessary
with lower risk/higher knowledge
Hypothetical ScenariosRestoration of fish populations
in medium-sized / large rivers
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 29 / 29
Conclusions
• Compensatory habitats in impoundments can be
feasible and very effective, especially at the
head of impoundments or parallel to
impoundments
• In nature-like fishways and bypass-channels,
sedimentology & dynamic hydraulics need
more attention
• In series of impoundments, creation of
compensatory habitats may restore fish
populations much more effectively than
technical solutions for fish passage and fish
protection
Compensatory habitats | 10. Sept. 2018 | FIThydro, Augsburg 30 / 29
Thanks
All photos in this presentation: ezb-TB Zauner
For your attention!
The , which implemented many of the
measures shown in this presentation!