View
1
Download
0
Category
Preview:
Citation preview
Überschrift Fish passage restoration by means of
nature-like constructions -
ecological requirements versus
construction stability
Marq Redeker
Ruhrverband, Germany
1. Fish migration obstacles and their effects
2. Different types of upstream fish pass
constructions
3. Interdisciplinary approach in fish pass design with
focus on :
- development of design criteria by joint consideration
of ecological basics & engineering requirements
- examples of nature-like constructions
- monitoring & maintenance
4. Summary & conclusions
Presentation structure
Fish passage restoration by means of nature-like constructions
Dortmund Essen Duisburg
1. Fish migration obstacles
Fish migration obstacles in the Ruhr River Basin (4485 km²)
S ~ 1300 migration obstacles
Decline of eel species (ref. Quebec
declaration of concern, 2003)
History of fish pass designs
Mulheim fish ladder, 1920
1. Fish migration obstacles
Vertical Slot Pass
Stiftsmuhle (D)
Rhomboid-type pass
Horster Muhle (D)
Technical pool- or channel-type fish passes
2. Types of upstream fish pass constructions
Baffle fishway
Padworth Mill (GB)
Fish lifts
Buttenen Weir fish lift (CH) Lairg Dam fish lock (GB)
Fish locks
Special technical constructions
2. Types of upstream fish pass constructions
Rock-ramp fishway
Dussel (D)
Nature-like fish passes
2. Types of upstream fish pass constructions
Pool & boulder pass
Beckinghausen (D)
Cardinia Creek
bypass channel (VIC, AUS)
Interdisciplinary approach in fish pass design
3. Interdisciplinary approach in fish pass design
Ecological basics e.g.
- fish migration behaviours
- migration periods
- species distribution within river zones
- swimming performance of fish
- pot. natural species composition & population dynamics
- provisions for monitoring
Engineering requirements e.g.
- construction stability & durability
- hydraulic performance
- flood safety issues
- restrictions due to water legislation
- health and safety considerations
- operation & maintenance friendliness
BEST OPTIMUM DESIGN RECOMMENDATIONS
Following examples in view of fish pass efficiency,
i.e. traceability & passability
&
Traceability
3. Interdisciplinary approach in fish pass design
- rheoactive behaviour (i.e. orientation by the main current)
- migration right up to obstacle
Fish pass location, entrance position & attraction flow
Fish pass location
Traceability
3. Interdisciplinary approach in fish pass design
entrance position
attraction flow velocity & angle
Passability
- diadromous & potamodromous
migrations
- migration types & distances
- migration periods
3. Interdisciplinary approach in fish pass design
Freshwater
Sea
Fish pass operation times and conditions (Q30 - Q330 )
Passability
Trout zone
Grayling zone
Barbel zone
Bream
zone
River zones according to Huet, 1949
3. Interdisciplinary approach in fish pass design
Species distribution in river systems
Ruffe
zone
Swimming speed of fish
3. Interdisciplinary approach in fish pass design
Geometrical & hydraulic conditions in fish passes e.g.
- pool dimensions, slot spacings & water depths
Pool dimensions
Passability
Slot spacings
3. Interdisciplinary approach in fish pass design
Geometrical & hydraulic conditions in fish passes e.g.
- pool dimensions, slot spacings & water depths
Passability
Sufficient water depths on a pool & boulder-type rock-ramp fishway
Insufficient water depths on a rock-ramp fishway
3. Interdisciplinary approach in fish pass design
Geometric & hydraulic conditions in fish passes e.g.
- (max.) velocities & turbulences in migration corridor
Flow velocities measurements during test runs
Passability
vmax < 2 m/s
Dh < 0,2 m
3. Interdisciplinary approach in fish pass design
Design for a range of flows incl. design flood discharge
Construction stability and durability
rock-ramp fishway Olsberg in mean flow conditions rock-ramp fishway Olsberg
during a 2-year flood event
3. Interdisciplinary approach in fish pass design
Monitoring, operation and maintenance
Inlet structure with fish trap facility at a bypass channel
- provision of monitoring facilities is recommended
- permanent maintenance is required
Debris on a rock-ramp fishway
4. Summary & conclusions
Conclusions (1)
widespread distribution of nature-like fish passes
nature-like designs are gaining acceptance
worldwide
importance of fish passage restoration due to WFD
nature-like constructions are well-developed for
various species
Recommended