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

Can you see

something?

River continuity ... the widespread situation ...

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

Conclusions (2)

Channel-type fish passes Rock-ramp fishways

4. Summary & conclusions

Fish pass guidelines and

recommendations

Conclusions (one more to go ...)

4. Summary & conclusions

Conclusions (the last one!)

pot.

habitat

Thank you !

Catchment-wide concept for fish passage

restoration in the Ruhr River Basin

Ruhr corridor S 21,7 M€ 150.000 €/ha

Lenne corridor S 18,4 M€ 280.000 €/ha

Upstream passage restoration:

4. Summary & conclusions