Fish Passage

Principle• Make culvert NOT a velocity barrier to fish

• Compare to typical natural channel hydraulics

• Use V (section average) as indicator

Fish Passage

Design Flow Parameters:• Evaluate at Q > normal, Q < flood

• Choose Qfpd – only exceeded 5% of days

• Calculate hydraulically (no statistics)

Fish Passage

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% Time Flow Less Than

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Rati

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Fish Passage

YFPD = 0.8 – 34.3S ; min. YFPD = 0.2

Y98 envelope

Fish Passage

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020406080100120140160180200

Invert + Culvert

Energy Gradeline

Water Surface EL.

Top of Bank

Critical Depth

Normal Depth

Backwater from burial – Y up, V down

Fish Passage

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020406080100120140160180200

Invert + Culvert

Energy Gradeline

Water Surface EL.

Top of Bank

Critical Depth

Normal Depth

Backwater from burial – Y up, V down

Backwater effect lost- V > Vch?

Fish PassageVelocity Distribution in Culverts

Fish Passage

Velocity Reduction Options - Effective

• Increase Pipe Roughness – long culverts, steep grades (normal flow)

• Use Multiple Pipes – wide, shallow channels; consider drift blockage

• Use Wider Shape (Box, Ellipse) – cost vs bridge

Fish PassageVelocity Reduction Options – NOT Effective• Increase Pipe Diameter - mostly air space

• Increase Burial – ineffective >1m, ponding, u/s barrier, excavation?

Fish Passage

Substrate

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XS Station (m)

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Fish Passage

Substrate Holders:• Ht. = 0.3m (0.2m for D<3m)• Space = Ht / S (Min. 7m)• Class 1M or 1 Rock Substrate• Only where V > Vch (U/S)

Fish Passage

Y n - Class 1M n - Class 1

0.1 0.161 0.2 0.079 0.1410.3 0.064 0.0950.4 0.057 0.0790.5 0.053 0.0710.6 0.050 0.0650.7 0.048 0.0620.8 0.047 0.0590.9 0.046 0.0571.0 0.045 0.0551.1 0.044 0.0541.2 0.044 0.0531.3 0.043 0.0521.4 0.043 0.0511.5 0.042 0.050

Substrate - Impact on Roughness

Fish Passage

Fish Passage• Channel parameters: B = 3.0 m, h = 1.5 m, T = 7.0 m, S = 0.012 • Design flow parameters of Qdes= 36 cms, Ydes= 2.25 m, Vdes= 2.8 m/s • Culvert structure: D = 3670 mm, L = 86 m, Burial = 0.925 m, S = 0.012

• For S = 0.012 m/m, YFPDD = 0.39 m, QFPDD= 1.3 cms, VFPDD = 0.9 m/s

Fish Passage