Västerkvarn HPP, river

Kolbäcksån First migrating fish in a 100 years…

Site conditions

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• Kolbäcksån tributary to Galten, lake Mälaren with MQ 29 m3/s

• Västerkvarn most downstream migration obstacle, about 5 km from lake Mälaren

• Migratory fish species mainly Aspius aspius, Salmo trutta and Anguilla anguilla

• HPP built 1915 with QMAX: 45 m3/s

• HHPP: 6,7 m; HDAM: 2,8 m

• Problems regarding debree, ice buildup, head loss

• Complex site. canal, historical mill, bridges etc.

• Challenging site conditions and time schedule!

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Time plan

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• March: establishment, coffer

dams etc. Decision to adapt

HPP for migratory fish

• April: demolition works

• May-jul: foundation works etc.

• Aug-nov: concrete works

• Dec: first comissioning new

station

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Solutions

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Solutions

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Results

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After construction

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After construction

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After construction

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After construction

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Evaluation (early results)

• Counter deployed april 2016

• Within 1 week Aspius aspius passed

• Local record spawning of A. aspius

• Counter technichal issues – not reliable results

• Spawning A. aspius observed in uppermost pool

• S. trutta, A. anguilla, A. brama, R. rutilus, P. fluviatile

• Up- and downstream migration about same numbers of fish

• Mainly trout observed in bypass, also bream, perch and roach

Conclusions

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• Evaluation started before

construction had finished…

• Improved cost efficiency

coordinating projects (in this

case about 30% for fishway)

• Construction type of vertical

slot, not always cost effective

• Low incline, small spaced trash

racks works fine, but demands

adapted cleansing, especially

hydrodynamically shaped ones

Work just started…

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• Upstream HPP´s will be

evaluated for possible fish

migration solutions, dam

removal etc.

• HPP´s in river Hedströmmen,

Rällsälven and Svartån:

ongoing work for fish migration

and reproduction measures

Thank you for the attention!

2016-08-30 18 Mälarenergi